Question 876667
Given that y varies directly with x then, y = kx for some k in R ----(1)
So, for x = 7, y = 63 replacing this values in (1)
We have, 63 = 7k => k = 63/7 => k = 9.
For x = 20 using (1) and k = 9, we have that y = (9)(20) = 180.
therefore, y = 180 when x = 20.