Question

Find the value of y when x = 10, if y = 35 when x = 7.

Answer 1

Set up a proportion:

y = 35 when x = 7

y = ? when x = 10

To get x from 7 to 10, you have to multiply by $\frac{10}{7}$. Therefore, you do the same to 35, and you get:

$35 \times \frac{10}{7} = 50$

And your answer is 50 :)

Answer 2

In this example, we know that x = 10 when y = 35 so the first set of coordinates are as followed.

(10) (35) =

We want to know the value of y when x is equal to 7, so our other coordinates will be as followed.

(10) (35) = (7) (Y)

Now, we can simplify by multiplying.

10 × 35 = 350

7 × y =  7y

Now, we have

350 =7y

÷7     ÷7   ← divide by 7 on both sides

50 = y

Therefore, the value of Y when X = 7 is Y = 50.