Question

If y varies directly as x and y = 70 when x = 10, find y when x = 36.
252

2,520

25,200

5.14

Answer 1

Answer:

252

Step-by-step explanation:

y varies directly with x means y=kx where k is a constant.

A constant means it never changes no matter what the point (x,y) they give.

So y=kx means y/x=k (I just divided both sides by x here).

So we have the following proportion to solve:

$\frac{y_1}{x_1}=\frac{y_2}{x_2}$

$\frac{70}{10}=\frac{y_2}{36}$

70/10 reduces to 7:

$7=\frac{y_2}{36}$

Multiply both sides by 36:

$7(36)=y_2$

Simplify left hand side:

$252=y_2$

So y is 252 when x is 36.