U is inversely proportional to the cube of V and U = 81 when V = 2. Find U when V = 3
-
A.
24 -
B.
27 -
C.
32 -
D.
36
Correct Answer: Option A
Explanation
U (propto frac{1}{V^3})
U = (frac{k}{V^3})
k = UV(^3)
k = 81 x 2(^3) = 81 x 8
When V = 3,
U = (frac{k}{V^3})
U = (frac{81 times 8}{3^3})
U = (frac{81 times 8}{27}) = 24
There is an explanation video available below.