Question

If y varies directly as x, and y = 20 as x = 4, find the y for the x-value of 5.

A) 24

B) 25

C) 26

D) 27

Answer 1

@zepdrix, can you help me?

Answer 2

Do you know how to write the direct variation formula?

Answer 3

Nope. I have very poor math skills, unfortunately. I've tried to learn math and failed. It is like a foreign language to me.

Answer 4

Oh my. Well good thing this one is pretty easy then! The direct variation formula in this case (and there are others but you only need one right now) is y = kx, where k is the constant of variation. Using the initial values of x and y they give you, you will solve for k. Then you will use that k value to find what they are asking for in the second part.

Answer 5

Using y = kx and filling in our y and x, we have 20 = 4k. Can you solve that for k?

Answer 6

5=k?

Answer 7

Yes, that is correct! You're not bad at math! Ok...now use that k value in for the next part of the problem. They ask you to find y when x is 5. Using the direct variation formula again, we have y = kx, and y = (5)(5) (one 5 is your k value you found and the other 5 is the x value they give you). What is 5*5?

Answer 8

That's simple haha, 25!

Answer 9

And that's all there is to it!

Answer 10

that is direct variation. Indirect, or inverse, variation is y = k/x.

Answer 11

And that one is just as simple to solve. Good job! See...you're not bad at math at all!

Answer 12

TY for the medal!

Answer 13

Of course! Thank YOU for the help!

Answer 14

You're welcome! Any time!