Question

Suppose P varies directly with d , and p=7 when d=3.
What is the value of d when p=28?

A. 140/3
B. 12
C. 16
D. 4/3

Answer 1

p vaires directly with d means
p=kd
7=k3
divide by 3
7/3=k

28=(7/3)d
times 3/7 both sides
84/7=d
12=d

B