find y when x=15 if y=6 when x=30

Question

i do not now how to do this ther the teacher told me.

Answer 1

y = 6 when x = 30

Direct variation equation is y = kx.

The given numbers form one ratio expressed as y/x = 6/30.

To find y, when x = 15

we set up another ratio y/15

By the definition both ratios are equal 6/30 = y/15

Multiple to each side by 15.

15 * 6/30 = 15 * y/15

y = 3.

When x = 15, y = 3.