Question

The value of y is directly proportional to the value of x.
If y = 12 when x = 15, what is the value of x when y = 40?
A.
12
B. 32
C.43
D.
50

Answer 1

Answer:

D

Step-by-step explanation:

Given y is directly proportional to x then the equation relating them is

y = kx ← k is the constant of proportion

To find k use the condition y = 12 when x = 15

12 = 15k ( divide both sides by 15 )

0.8 = k

y = 0.8x ← equation of proportion

When y = 40 , then

40 = 0.8x ( divide both sides by 0.8 )

50 = x → D