Posted by **Dippy** on Sunday, March 15, 2009 at 12:14am.

Suppose y varies directly as x and that y = 21 when x = 3. Find the value of y when x = 5.

Would I be wrong if I said y = 35? In using y = kx with the 21 and the 3 k = 7. So if y = 35 and x = 5 then k = 7. Am I correct or am I way off course?