Write a direct variation equation finding y when x=7?

Question

The variables x and y vary directly. When x=10,y=15. write a direct variation equation relating x and y and then find y when x=7?

Answer 1

Direct variation is in the form, y = kx

 

15 = k(10)

3/2 = k

 

y = (3/2)7

y = 21/2