Mathematics Middle School

A motorboat covers the distance from one pier to the other pier in 4 hours and the way back in 5 hours. What is the speed of the boat in still water, if it covers 70 km with the current in 3.5 hours?
(its not 20 i tried)

Answers

Answer 1
r = speed in still water
r + c = speed with current
r - c = speed against current

3.5(r + c) = 70
r + c = 20
c = 20 - r

4(r + c) = distance from pier to pier
5(r - c) = distance from pier to pier
4(r + c) = 5(r - c)
4(r + 20 - r) = 5(r - 20 + r)
80 = 10r - 100
180 = 10r
18 = r
The speed in still water is 18 km/hour

Related Questions

There are a total of 500 students in grades 1 through 5 in an elementary school. 17% of the total number of students are in 1st grade. 19% of the total number of students are in 4th grade. The number of 3rd-grade students is 9 less than the number of 4th-grade students. The number of 2nd-grade student is 10 less than the number of 5th-grade students. How many students are in each grade.

Answers

There are 0.17(500) or 85 students in grade 1.

There are 0.19(500) or 95 students in grade 4. 

The number of students in 3rd grade is 95-9 or 86 students.

So, there are a total of 266 students from grade 1,3 and 4. This leaves 234 students for grade 2 and grade 5. 

Let n be the number of students in 5th grade; n-10 is the number of students in 2nd grade. 
     [tex]n+\left(n-10\right)=234[/tex]

     [tex]2n=244[/tex]

     [tex]n=122[/tex]

There are 122 students in grade 5, and there are 112 students in 2nd grade. 

122 students in 5th grade, 112 in second grade

how many solutions does this system of equations have?
y= -3x + 7
y= -3x -6

choices
a. infinitely many
b. 2
c. 1
d. 0

Answers

The first step for solving this expression is to know that since both of the expression are equal to y,, we must set them each to each other to form an equation in x. This will look like the following:
-3x + 7 = -3x - 6
Now cancel equal terms on both sides of the equation.
7 = -6
This tells us that the statement is false for any value of x and y,, so our answer is (x,y) ∈ ∅,, or no solution (option D).
Let me know if you have any further questions.
:)

First, I would like to know what is means when someone asks you to find the Means-To-Mad Ratio. I do not know what a Means-To-Mad Ratio is.
Second, can someone please answer this problem?

1. {15, 16, 17, 17, 17, 17, 18, 19}
2. {12, 13, 13, 14, 14, 14, 16, 16}
Calculate the means-to-MAD ratio for the two number sentences above.
Thank you.

Answers

MAD = Mean Absolute Deviation.
 so you need to calculate the mean ( average)  and then calculate the MAD ratio

see attached picture for how to calculate the MAD:

Kelly has 236 feet of fence to use to enclose a rectangular space for her dog. She wants the width to be 23 feet. Draw a rectangle that could be the space for Kelly's dog. Label the length and the width.

Answers

perimeter = 236 ft

length=?

p= 2l+2w

236=2l+2(23)

236=2l+46

190=2l

l= 95ft



Final answer:

To create the space for Kelly's dog, a rectangle with a length of 118 feet and a width of 23 feet should be drawn.

Explanation:

To draw a rectangle that could be the space for Kelly's dog, we need to consider the given information. Kelly has 236 feet of fence to use, and she wants the width to be 23 feet.

Since the opposite sides of a rectangle are equal in length, we can divide the total amount of fence by 2 to determine the length of each side. 236 feet / 2 = 118 feet.

So, the rectangle that could be the space for Kelly's dog would have a length of 118 feet and a width of 23 feet.

The mean of 4 numbers is 22. What would the new mean be if the number 18 is added to the data set?
A. 17.2
B. 40
C. 21.2
D. 26.5

Answers

The new mean would be C: 21.2
How do you find the mean? You add the numbers up and divide by the amount in the set. So, we have to go backwards. Since we divided, we need to multiply 4 by 22. You get 88. Now add that new number of 18 to 88 to get 106. Now there are 5 numbers in the set so you divide 106 by 5 to get 21.2. So the answer is C. 21.2! Hope this helps!

for the diagram below which equation is the correct use of the distance formula


the last one D is
D= √(11-6)^2 + (5-y2)^2

Answers

the Answer is A, verified apex 

Answer: The correct equation is,

[tex]6.71=\sqrt{ (11-5)^2+(y_2-6)^2}[/tex]

Step-by-step explanation:

If [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex] are the endpoints of a line segment,

Then by the distance formula,

The length of the line segment is,

[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

Here, (5,6) and (11, [tex]y_2[/tex] ) are the endpoint of the line segment which has the length 6.71,

Thus, d = 6.71, [tex]x_1=5[/tex] [tex]y_1=6[/tex], [tex]x_2=11[/tex]

[tex]\implies 6.71 = \sqrt{ (11-5)^2+(y_2-6)^2[/tex]

Which is the required equation.

Find the distance between -3 and 4.
A) -12
B) -7
C) -1
D) 7

Answers

The distance between -3 and 4 is D. positive 7. Since you are moving forward 7 places, the answer would be positive, However, if you were moving backwards, it would be -7.

I hope this helps.

Answer:

i just did it its positive 7

Step-by-step explanation:

Jennie says the experimental probability that a 7th grade student reads at least 100 pages per week is 16/125. What is her error and the correct experimental probability?


HERE IS THE CHART

| pages       | 6th | 7th | 8th| {Grades}

| 75 pages   | 24 | 18 | 22 |

| 100 pages | 22 | 32 | 24 |

| 150 pages | 30 | 53 | 25 |

Answers

The correct probability is 85/103.  Her errors were that she only took the number of 7th grade students that read 100 pages per week; she did not include the number of students that read more than that, and she wrote the denominator of the probability as the number of pages read instead of the total number of seventh grade students.

32 seventh grade students read 100 pages per week.  53 students read 150 pages per week.  This is out of 18+32+53=103 seventh grade students.  This gives us 32+53=85/103.

Jennie incorrectly calculated the experimental probability of a 7th grader reading at least 100 pages per week. The correct calculation is the sum of 7th graders who read 100 and 150 pages, divided by the total number of 7th graders, resulting in an experimental probability of 85/103.

Jennie's error lies in calculating the experimental probability that a 7th grade student reads at least 100 pages per week incorrectly. To find the correct experimental probability, we need to add the number of 7th graders reading 100 pages and those reading 150 pages, then divide by the total number of 7th graders. According to the chart, 32 read 100 pages and 53 read 150 pages. The total number of 7th graders is the sum of students reading 75, 100, and 150 pages, which is 18 + 32 + 53 = 103. So, the correct experimental probability is (32 + 53) / 103 = 85 / 103.

I’m not sure this I’m so confused in algebra

Answers

|x+4| = 3x - 5

x + 4 = 3x - 5
2x = 9
  x = 9/2

-(x+4) = 3x - 5
-x -4 = 3x - 5
   4x = 1
     x = 1/4

answer
x = 1/4
x = 9/2

Which answer describes the transformation of f(x)=x2−1 to g(x)=(x−1)2−1 ?




a vertical translation 1 unit up

a vertical translation 1 unit down

a horizontal translation 1 unit to the right

a horizontal translation 1 unit to the left

Answers

[tex]f(x)=a(x-h)^2+k\ \text{where (h; k) are coordinates of the vertex}[/tex]


[tex]f(x)=x^2-1\ \ \ vertex (0; -1)\\\\g(x)=(x-1)^2-1\ \ \ vertex(1;-1)[/tex]



Answer: a horizontal translation 1 unit right.

Which it true about modeling a solution to an addition problem on a vertical number line?

A. When adding a negative number, you move down

B. When adding a positive number, you move down

C. Locating the sum is not necessary.

D. Locating the sum is the first step

Answers

Part A is correct :)

Answer:

A. When adding a negative number, you move down

Step-by-step explanation:

Actually, according to transformation of functions, there's two types of transformation, those that only involve translation, and those that change the dimension of the function.

In this case, modelling a solution to an addition problem, we know that adding a negative number, the function will move downs, because in that case we will be transformation or "changing" the y-variable, that's why it will move vertically.

Therefore, the right answer is A.

Realy Need this Right away

Answers

I think it will be D. 

(not super positive) 

Tell me if i'm right or wrong plz!!!

Hope this helped!

:)
hey,
the answer is C
i hope that helped

using the distributive property,which of the following expression is equivalent to 4(3+4y) 12+16y,12+4y,7+4y,7+8y

Answers

(4x3) + (4x4y) = 12 + 16y
The answer is 12 + 16y.
4(3+4y) = (4 x 3)+(4 x 4y) = 12 + 16y

How is the graph of y= 1/3x related to its parent function y=1/x

Answers

Vertical contraction: g (x) = k · f (x)
 When you multiply the y coordinate of the original function f (x) by a constant k:
 If 0 <k <1, the function contracts on the y axis
 We have then:
 y = k * (1 / x)
 Where,
 k = 1/3
 y = (1/3) * (1 / x)
 y = 1/3x
 Answer:
 the function contracts on the y axis

a normal distribution pf data has a mean of 15 and a standard deviation of 4 how many standard deviations from the mean is 25

Answers

Answer:

c 2.5

Step-by-step explanation:

Answer:

2.5

Step-by-step explanation:

:)

Which of the following numbers is between 0.40 and 0.47?
A) 7/50
B) 19/50
C) 21/50
D) 43/50

Answers

C is the correct answer


it's equal to 0.42




good luck
21/50 = 0.42

0.42 is between 0.40 and 0.47

answer
C) 21/50

a basketball court is a rectangle with a perimeter of 1040 feet. The length is 200 feet more than the width. What is the width and length of the basketball court?

Answers

if you do 1040-400 you get 640
then you need to divide that by 4 to get 160 leaving you with the width, to get the length you have to add 200 to the width meaning the length is 360

length = 360
width = 160
Length = width + 200

[tex]x + x + x + 200 + x + 200 = 1040 \\ 4x + 400 = 1040 \\ 4x = 640 \\ x = 160[/tex]
Length = 160 + 200 = 360 feet

Answer :
Width = 160 feet,
Length = 360 feet

Hope this helps. - M

find by completing the square

Answers

[tex]y=ax^2+bx+c\\\\y=a(x-h)^2+k\ where\ h=\dfrac{-b}{2a};\ k=f(h)=\dfrac{-(b^2-4ac)}{4a}[tex]y=-3x^2+7x-5\\\\a=-3;\ b=7;\ c=-5\\\\h=\dfrac{-7}{2\cdot(-3)}=\dfrac{7}{6}\\\\k=\dfrac{-(7^2-4\cdot(-3)\cdot(-5)}{4\cdot(-3)}=\dfrac{-49+60}{-12}=-\dfrac{11}{12}\\\\y=-3\left(x-\dfrac{7}{6}\right)^2-\dfrac{11}{12}[/tex]


from a class containing 12 girls and 10 boys , students are to be selected to serve on a school advisory panel.

Answers

what is your question?

two more than the product of a number and 8 is 5

Answers

When ever the problem says is, the next number after that is going to be the answer to the equation. So now you have =5.

Next it say two more which means adding so now we have, +2=5

Now we have the product of a number and 8. This means that the number and 8 equal the product. Now we know that an answer that is a product is a multiplication problem. That means that you have to multiply 8 and the number.

That leaves us with the answer, n•8+2=5

The unknown number is [tex]\( \frac{3}{8} \).[/tex]

Let's solve the problem step by step.

Given: Two more than the product of a number and 8 is 5.

Let's denote the unknown number as [tex]\( x \)[/tex].

According to the problem, we can express the given condition in an equation:

[tex]\[8x + 2 = 5\][/tex]

To find the value of [tex]\( x \)[/tex], we need to isolate it on one side of the equation. We'll begin by subtracting 2 from both sides to get rid of the constant term on the left side:

[tex]\[8x = 5 - 2\][/tex]

[tex]\[8x = 3\][/tex]

Now, to solve for [tex]\( x \)[/tex], we'll divide both sides of the equation by 8:

[tex]\[x = \frac{3}{8}\][/tex]

So, the solution to the equation is [tex]\( x = \frac{3}{8} \).[/tex]

Now, let's provide a brief explanation:

The equation [tex]\(8x + 2 = 5\)[/tex] is formed based on the given problem statement. By subtracting 2 from both sides and then dividing by 8, we isolate the variable [tex]\( x \)[/tex] to find its value, which is [tex]\( \frac{3}{8} \).[/tex]

Thus, the correct answer is:

[tex]\[ x = \frac{3}{8} \][/tex]

Complete question:

Two more than the product of a number and 8 is 5

Please help me! Show work thank you so much

Answers

A quadrilaterals angles = 360°

three angles are given, with the fourth as x: 90, 80, 74, x

Add all the angles together and set it equal to 360

90 + 80 + 74 + x  = 360

Simplify. Combine like terms

x + 244 = 360

Isolate the x, subtract 244 from both sides

x + 244 (-244) = 360 (-244)

x = 360 - 244

x = 116

116° is your answer

hope this helps

Which is the graph of the function f(x) =1/2x^2-6

Answers

Well it is gonna be compressed inward and down 6 post the graph

What is the m∠ACB? 10° 50° 90° 180°

Answers

The total sum of angles in a triangle is 180, thus the value of ∠ACB will be obtained as follows:
Given that the triangle is a right triangle, the sum of angles will be:
(4x)°+(7x-20)°+90=180
simplifying and solving for x we get:
4x+7x-20+90=180
11x=180+20-90
11x=110
dividing both sides by 11 we get:
(11x)/11=110/11
this gives us
x=10°
Thus substituting the value of x in:
∠ACB=(7x-20)° 
=(7*10-20)
=70-20
=50°

Answer: 50°

Answer:

50°

Step-by-step explanation:

90 + 4x+ 7x - 20(+20) = 180 + 20

4x + 7x = 200 - 90

4x + 7x = 110

11x/11 = 110/11

X = 10

m∠ACB =  7x - 20 = 7(10) -  20 = 50

Brian wants to buy a motorcycle and is planning to get motorcycle insurance. Suppose the average accident rate is 0.1, and the average expenses incurred on accidents is $38,000. The insurance plan has a yearly premium of $1,000 and a deductible of $4,000.
If after 4 years of insuring 100 people, 9 motorcycle drivers had an accident, where does the company stand after money has been taken in and paid out for this group of 100 insured people?

$85,500
-$36,000
$94,000
$58,000

Answers

It's $94,000
 
1,000 X 100 X 4 = 400,000

Answer:

The correct option is $94,000

Step-by-step explanation:

Yearly premium under the insurance plan = $1,000

Total premium from single motorcycle driver in 4 years = $1,000 * 4 = $4,000

Number of people insured = 100

Total premium collected from 100 motorcycle drivers = $4,000 * 100 = $400,000

Average expenses incurred on accident = $38,000

Deductible = $4,000

Net expenses incurred per accident = $38,000 - $4,000 = $34,000

In 4 years , 9 motorcycle drivers had an accident

Total expenses incurred for accident = $34,000 * 9 = $306,000

Net savings of Insurance Company = total premium - total expenses = $400,000 - $306,000 = $94,000

Hope it helps.

Thank you !!

Angles that are located outside the triangle are called (blank)

the sum of the exterior angles of a triangle is (blank) degrees

what are remote interior angles?

Answers

1. Exterior
2. 360°
3. remote interior angles are angles that would equal a exterior angle when added together

Ms. Ito's art class used 2/3 of bottle of blue paint. If they used 1/4 as much red paint as blue paint. How many bottles of red paint did they use?

Answers

The answer is 1/6 bottles of red paint. For how I got it was I multiplied 2/3*1/4 which was 2/12 and when u simplify it, your answer is 1/6. Hope this helped!!!

Final answer:

The class used 2/3 of a bottle of blue paint and 1/4 as much red paint, which means they used 1/6 of a bottle of red paint.

Explanation:

To solve the problem presented by Ms. Ito's art class, we first need to determine the amount of blue paint used and then calculate the red paint used based on that amount. The class used 2/3 of a bottle of blue paint. Since they used 1/4 as much red paint as blue paint, we need to divide the amount of blue paint by 4 to find the amount of red paint used.

Calculation: (2/3) ÷ 4 = 2/3 ÷ 1/4 = (2×1)/(3×4) = 2/12 = 1/6

Therefore, the class used 1/6 of a bottle of red paint.

mrs.pappert left her house a quater past 7:00. At what time did she leave her house

Answers

She left her house at 7:15
A quarter past is 15 minutes past. 

Mrs. Pappert left her house at 7:15.

jalen deposited 3 370 into a savings account that earns 1.8% simple intrest each year calculate the intrest jalen earns after 4 years

Answers

Answer:

17.5

Step-by-step explanation:

The radius of the earth's orbit is 45,000,000 meters. What is the number in scientific notation?

A) 4.5 x 10-7
B) 4.5 x 107
C) 45 x 10-6
D) 45 x 106

Answers

The answer is 4.5 × 10^7
I would say C because if u move the decimal to the right 7 places, you would get 45,000,000

A video game was $38. This weekend the game will be marked 13 percent off. How much is the game this weekend?

Answers

Discount = 13% x $38 = 0.13 x 38 = $4.94

Cost of the game after discount = $38 - $4.94 = $33.06

Answer:  $33.06
Final answer:

The video game was originally $38. This weekend it is 13% off. After applying this discount, the game will cost $33.06.

Explanation:

The subject of your question lies in the realm of Mathematics, specifically focusing on a practical application: calculating a discount. In this case, the video game was originally $38 and this weekend, there is a discount of 13%. Since the discount is a percentage off of the original price, you need to multiply $38 by 13% (or 0.13, when presented as a decimal).This operation gives us: $38 * 0.13 = $4.94.This means the discount is $4.94. To find out how much the video game costs after the discount has been applied, you need to subtract this amount from the original price of the game. Therefore, the price of the game this weekend will be: $38 - $4.94 = $33.06.

Learn more about Calculating Discounts here:

https://brainly.com/question/32761587

#SPJ12

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