the variable y varies as x: y is 12 when x is 4.find x when y is 18.

Question

find x when y is 18.

Answer 1

y = 12 when x = 4

Direct variation equation is y = kx.

The given numbers form one ratio expressed as y/x = 12/4

To find x, when y = 18

we set up another ratio 18/x

By the definition both ratios are equal 12/4 = 18/x

Divide each side by 18.

(12/4)/18 = (18/18x)

1/6 = 1/x

x = 6.