In how many months, at a rate of 6% compound interest per annum, will a sum of ₹1,200 become ₹1,348.32.? 

This question was previously asked in
RPF Constable 2024 Official Paper (Held On 02 Mar, 2025 Shift 3)
View all RPF Constable Papers >
  1. 24 months
  2. 30 months
  3. 18 months 
  4. 12 months

Answer (Detailed Solution Below)

Option 1 : 24 months
Free
RPF Constable Full Test 1
3.9 Lakh Users
120 Questions 120 Marks 90 Mins

Detailed Solution

Download Solution PDF

Given:

Principal (P) = ₹1,200

Amount (A) = ₹1,348.32

Rate of interest (R) = 6% per annum

Formula Used:

Compound Interest Formula: A = P \((1 + \frac{R}{100})^n\)

Calculation:

We need to find the number of months (n).

Given:

₹1,348.32 = ₹1,200 \((1 + \frac{6}{100} )^\frac{n}{12}\)

⇒ 1.1236 = \((1.06)^\frac{n}{12}\)

Taking natural logarithm on both sides:

\(ln(1.1236) = \frac{n}{12} × ln(1.06)\)

⇒ \(\frac{n}{12} = ln(1.1236) / ln(1.06)\)

⇒ \(\frac{n}{12} = 0.1167 / 0.0583\)

⇒ \(\frac{n}{12} = 2\)

⇒ n = 2 × 12

⇒ n = 24

Hence, the number of months required is 24 months.

Alternate Method Given:

Principal = ₹1200

Amount = ₹1348.32

Rate = 6% per annum

Calculations:

A = P × (1.06)t

Start multiplying year by year until we reach 1348.32

Year 1: 1200 × 1.06 = 1272

Year 2: 1272 × 1.06 = 1348.32 

∴ Time = 2 years = 24 months

Latest RPF Constable Updates

Last updated on Jul 16, 2025

-> More than 60.65 lakh valid applications have been received for RPF Recruitment 2024 across both Sub-Inspector and Constable posts.

-> Out of these, around 15.35 lakh applications are for CEN RPF 01/2024 (SI) and nearly 45.30 lakh for CEN RPF 02/2024 (Constable).

 

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

More Compound Interest Questions

More Interest Questions

Get Free Access Now
Hot Links: teen patti fun teen patti all game teen patti royal teen patti master game teen patti sequence