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2 years ago

10

Josephine can correct her students' test papers in 9 hours, but if her teacher's assistant helps, it would take them 7 hours. Ho

w long, in hours and minutes, would it take the assistant to do it alone? (Write your answer in mixed units. Enter a zero in any unneeded blanks.)

1 answer:

kirill [66]2 years ago

7 0

Using the together rate, it is found that it would take the assistant 31 hours and 30 minutes to do it alone.

<h3>What is the together rate?</h3>

It is the sum of each separate rate.

In this problem, the rates are given as follows:

Josephine: 1/9.

Assistant: 1/x.

Together: 1/7.

Hence:

$\frac{1}{9} + \frac{1}{x} = \frac{1}{7}$

$\frac{x + 9}{9x} = \frac{1}{7}$

$9x = 7x + 63$

2x = 63

x = 31.5.

It would take the assistant 31 hours and 30 minutes to do it alone.

More can be learned about the together rate at brainly.com/question/25159431

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PLEASE ANSWER!!

ohaa [14]

Answer: 5 games

Step-by-step explanation: They need to win half their games for a .500 record and half or 30 is 15. They already won 10 so they need to win 15- 10 = 5 more games to have a .500 record.

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2 years ago

Help me find the answer!! 2-step equation

Vladimir79 [104]

$\looparrowright \sf3\leqslant \dfrac{y}{ - 5} + 7$

$\looparrowright \sf3 - 7\leqslant \dfrac{y}{ - 5}$

$\looparrowright \sf - 4\leqslant \dfrac{y}{ - 5}$

$\looparrowright \sf - 4 \times - 5\leqslant {y}$

$\looparrowright \sf 20\leqslant {y}$

8 0

2 years ago

Solve the following system of equations by substitution and select the correct answer below:

Alexxx [7]

Okay so for substitution, chose one of of the equations to solve for x. Let's solve for the second one. So you have 2x-8y=32.
Start by adding 8y to both sides:
2x=8y+32.
Then you have to get x by itself so you divide both sides by 2 which will give you:
x=4y+16.

Now you have:
6x-4y=36
x=4y+16 (this was 2x-8y=32)

Now, plug in the second equation to the first one. You would do so by plugging in the second equation to where you see x. You would have:
6(4y+16)-4y=36

Now, multiply the 6 with the 4y and 16. you would then have:
24y+96-4y=36.

Now, combine your like terms to get:
20y+96=36
Then subtract 96 to both sides:
20y=-60
Then divide both sides so that you have y all by itself:
y=-30!

You now have the answer for y, so now plug what you got for y into the other equation: x+4y=16:
x+4(-30)=60
Solve for x:
x-120=60
add 120 to both sides:
x=180!
so Your answer is Y=-30 and X=180

I hope this helped:)

5 0

3 years ago

Read 2 more answers

Answer this<br> PLz i needs to get this done there will be more questions stay alert thank you

Zarrin [17]

The answer is 89,760 feet.

6 0

3 years ago

Find the extreme values of the function f(x, y) = 4x2 + 6y2 on the circle x2 + y2 = 1.

julia-pushkina [17]

Answer with Step-by-step explanation:

We are given that

$f(x,y)=4x^2+6y^2$

Let g(x,y)= $x^2+y^2=1$

We have to find the extreme values of the given function

$\nabla f(x,y)$

$\nabla g(x,y)=$

Using Lagrange multipliers

$\nabla f(x,y)=\lambda \nabla g(x,y)$

$f_x=\lambda g_x$

$8x=\lambda 2x$

Possible value x=0 or $\lambda=4$

If x=0 then substitute the value in g(x,y)

Then, we get $y=\pm 1$

$f_y=\lambda g_y$

$12y=\lambda 2y$

If $\lambda=4$ and substitute in the equation

Then , we get possible value of y=0

When y=0 substitute in g(x,y) then we get

$x=\pm 1$

Hence, function has possible extreme values at points (0,1),(0,-1), (1,0) and (-1,0).

$f(0,1)=6$

$f(0,-1)=6$

$f(1,0)=4$

$f(-1,0)=4$

Therefore, the maximum value of f on the circle $x^2+y^2=1$ is $f(0,\pm1)=6$ and minimum value of $f(\pm1,0)=4$

7 0

3 years ago