if y is directly proportional to x,y is 10 when x is 3.what is the value of y when x is 5

Answer 1

y = kx, where k is constant of variation

use values of 10 for y and 3 for x to find k:

10 = k3, so k = 10/3

so y = 10/3 * x

when x = 5

y = 10/3 * 5 = 50/3