Bank Preparation
Bank Math
Simple and Compound Interest
ব্যাংক নিয়োগ
Combined Bank
Combined 9 Banks & 2 Financial Institution Post: Senior Officer(05-12-2025)
Combined 9 Banks & 2 Financial Institution Post: Senior Officer(05-12-2025)
A sum of money doubles itself in 8 years at a certain rate of simple interest. In how many years will it become four times itself at the same rate of interest?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
ক (24)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Given that,
The sum doubles itself in 8 years.
Amount after 8 years = 2P
Simple Interest for 8 years = P
We know,
SI = (P × r × n)/100
⇒ P = (P × r × 8)/100
⇒ 8r = 100
⇒ r = 100/8
∴ r = 12.5% per year
Now, we want to find in how many years the sum becomes four times itself.
Amount = 4P
Interest needed = 4P - P = 3P
We know,
SI = (P × r × n)/100
⇒ 3P = (P × 12.5 × n)/100. ; [r = 12.5%]
⇒ 3 = (12.5 × n)/100
⇒ n = (3 × 100)/12.5
∴ n = 24 years
∴ The sum will become four times itself in 24 years.
