Question

If y varies directly as x and y=8 when x=2, find y when x=6

Answer 1

y = 8

Explanation:

If y varies directly as x we can write y = kx where k is some constant.

Y = 8 when x = 2 so 8 = k*2

k = 8/2 = 4

so y = 4x

This is the equation of variation.

When x = 6, y = 4*6 = 24 (answer).

Answer 2

y =24

Explanation:

The equation for direct variation is

y =kx

If we know x and y we can solve for k

y=kx

8 =k*2

Divide each side by 2

8/2 = k2/2

4 =k

y =4x

We want to find y when x=6

y =4*6

y =24