If the radius of the base of a right circular cylinder is decreased by 30% and its height is increased by 224%, then what is the percentage increase (closest integer) in its volume?

This question was previously asked in
RPF Constable 2024 Official Paper (Held On 02 Mar, 2025 Shift 3)
View all RPF Constable Papers >
  1. 83%
  2. 70%
  3. 59%
  4. 58%

Answer (Detailed Solution Below)

Option 3 : 59%
Free
RPF Constable Full Test 1
3.9 Lakh Users
120 Questions 120 Marks 90 Mins

Detailed Solution

Download Solution PDF

Given:

Radius decreased by 30% ⇒ New radius = 70% = 0.7r

Height increased by 224% ⇒ New height = 324% = 3.24h

Formula used:

Volume of cylinder = πr2h

% Increase = \(\left(\frac{\text{New Volume} - \text{Old Volume}}{\text{Old Volume}}\right) \times 100\)

Calculations:

New volume = π(0.7r)2 × 3.24h = πr2h × (0.49 × 3.24)

⇒ New Volume = πr2h × 1.5876

⇒ % Increase = (1.5876 - 1) × 100 = 58.76%

∴ Volume increases by approximately 59%

Latest RPF Constable Updates

Last updated on Jun 21, 2025

-> The Railway Recruitment Board has released the RPF Constable 2025 Result on 19th June 2025.

-> The RRB ALP 2025 Notification has been released on the official website. 

-> The Examination was held from 2nd March to 18th March 2025. Check the RPF Exam Analysis Live Updates Here.

More Mensuration Questions

Get Free Access Now
Hot Links: teen patti stars teen patti dhani teen patti rules all teen patti game teen patti bliss