Question

If there is direct variation and y = 27 when x = 4, find y when x =12.

A. 9
B. 81
C. 1.78
D. 0.56

Answer 1

B

Explanation:

Given y and x vary directly then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = 27 when x = 4 , then

27 = 4k ( divide both sides by 4 )

`(27)/(4)` = 6.75 = k

y = 6.75x ← equation of variation

When x = 12 , then

y = 6.75 × 12 = 81