The radius of a cylindrical vessel is increased by 50% and the height is decreased by 50%.What is the change in its volume?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 12.5% increase.
Let the original radius(r1) be 20 cm and the original height(h1) 10 cm
The volume of the cylinder = πr12h1
22/7 × 20 × 20 × 10 = 12571.42 cm3
The increased radius = 150% of 20 = 30 cm
The increased height = 50% of 10 = 5 cm
The volume of the cylinder = πr22h2
22/7 × 30 × 30 × 5 = 14142.85 cm3
% change in volume = (14142.85 - 12571.42)/12571.42 × 100 = 12.5%