Question

Variable y varies directly with x2, and y = 96 when x = 4.

What is the value of y when x = 2?

Answer 1

varies directly so y = Kx^2 where k is a constant
y/x^2 = k
for 2 sets of values x1, y1 and x2, y2 k will be the same
y1/x1^2 = y2/x2^2
let (x1, y1) = (4, 96) and (x2, y2) = (2, y)
substitute and solve for y