Question

If y varies directly as x, and y=6 when x=15, find y when x=2.

A.) 4/5

B.) 4

C.) 5

d.) 5/4

Answer 1

Option A: 4/5

Explanation:

If y varies directly as x written as y ∝ x, this can be written as an equation:
y = kx where k is a constant

Since y = 6 when x = 15:
6 =k · 15

6 = 15k

15k = 6

k = 6/15 = 2/5

The equation beocmes
y = (2/5) x

Therefore when x = 2,

y = (2/5) x 2 = 4/5

Option A: 4/5