Question

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In how many years will a sum be double of itself at 10% p.a. simple
interest.
a) 10years
b) 20years
c) 19years
d) 5years
a
b​

Answer 1

Answer:

Option a

Step-by-step explanation:

Given:-

Rate of interest = 10% per annum

To find:-

In how many years will a sum be double of itself at 10% p.a. simple interest ?

Solution:-

Let the sum be Rs. X

Let the time be T years

Rate of Interest = 10%

Amount = Double the sum = Rs. 2X

We know that

Amount = Principle + Interest

=> Interest = Amount - Principle

=> Interest = 2X-X

Interest = Rs. X

Simple Interest (I) = PTR/100

=> T = (100×I)/PR

=> T = (100×X)/(X×10)

=> T = 100X/10X

=> T = 10

Time = 10 years

Answer:-

Required time for the given problem is 10 years

Used formulae:-

• Simple Interest (I) = PTR/100

• Amount = Principle + Interest

• P = Principle
• T = time
• R=Rate of interest
• I = Simple Interest