If the radius of the base of a right circular cylinder is decreased by 32% and its height is increased by 168%, then what is the percentage increase (closest integer) in its volume?

Correct option is A

Given:

Radius decreased by 32%
Height increased by 168%

Formula used:
Volume of cylinder = π × r² × h

Solution:​

Let original radius = r and original height = h

New radius = 0.68r (since 100% – 32% = 68%)
New height = 2.68h (since 100% + 168% = 268%)

Original volume = π × r² × h

New volume = π × (0.68r)² × 2.68h

New volume = π × r² × h × (0.4624 × 2.68)

Volume ratio = 0.4624 × 2.68 = 1.2392

Percentage increase = (1.2392 – 1) × 100 = 23.92% ≈ 24% increase in volume