Question

65. A sum of money becomes 2 times of itself in 8 years at certain rate of interest. Find the rate?
A) 12.5%
B) 8.5%
C) 10.5%
D) 14.5%

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Answer 1

Option A

Step-by-step explanation:

Given:-

A sum of money becomes 2 times of itself in 8 years at certain rate of interest.

To find:-

Find the rate of interest ?

Solution:-

Let the money be Rs. X

Therefore, Principle (P) = Rs. X

Let the Rate of interest be R

The sum becomes 2 times of itself in 8 years

Given time (T) = 8 years

Amount (A) = 2× Principle

=>A = 2 × P

Therefore, Amount = Rs. 2X

We know that

Amount = Principle + Interest

Interest = Amount - Principle

=> I = A - P

=>I = 2X - X

=>I = X

Therefore, Interest = Rs. X

We know that

Simple Interest (I) = PTR/100

=>R = (100×I)/PT

On substituting the values on the above formula then

=>R = (100×X)/(X×8)

=>R = 100X / 8X

=>R = 100/8

=>R = (25×4)/(2×4)

=>R = 25/2

=>R = 12 1/2 (or) 12.5

Therefore, Rate of interest = 12.5% (or)

12 1/2 %

Answer:-

The rate of interest for the given problem is 12.5%

Used formulae:-

• Interest = Amount - Principle

• I = PTR/100

• Where , I = Simple Interest,

• T = Time

• R = Rate of interest

• P = Principle

• A = Amount