It is given that y varies directly as x. if y = 5 when x = 4 determine the constant of variation. a) -4/5 b) 4 c) 5 d) 5/4

D) 5/4, I had this question on a quiz.

When one thing varies to another there is always a constant of variation. direct variation it is; y = kx

use the x,y values to find k
5 = 4k
5/4 = k

answer is D