Question

How do you do this and what's the answer? Explain plz.

Answer 1

Givens

Number of hours she studies = x = 6

Number of classes she misses = y

Test score = T = 90

Equation

T = x/(ky)

General Equation

Solve for y before you do anything else.

Multiply the entire equation by ky

T*ky = x Divide Both sides by Tk

y *kT/kT = x / (Tk)

y = x / kT

Now put the numbers in

y = 6 / k*90

That looks pretty much like A. doesn't it?

Answer 2

We are given that T = test score, and x = # of hours studied. We are given the same information in numbers:

T = 90

x = 6

y = ?

We need to figure out y in terms of k. Let's set up what we know:

$T = \frac{x}{ky}$

$90=\frac{6}{ky}$

Let's multiply both sides by y to get rid of it on the right side:

$90y = \frac{6}{k}$

Now, let's divide by 90 on both sides to get rid of it from the left side (and solve for y):

$y = \frac{6}{90k}$

Your answer is A! If any part didn't make sense, you know where to reach me.