If the radius of the base of a cylinder is increased by 20% and its height is decreased by 33 % , then what will be the change in percentage in its volume?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. decrease by 4%
Radius of the cylinder decreased by 20% = 1/5
Height of cylinder decreased by 33% = 1/3
Old : New
Radius 5 → 6
Height 3 → 2
Old volume = πr2h = 75π
New volume = πr2h = 72π
Percentage decrease in volume = (75π - 72π)/75π × 100 = 4% decreased