A sum increases by 48% in 6 years at certain rate of simple interest per annum, then how much years

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25 Aug 2022 Simple & Compound Interest

A sum increases by 48% in 6 years at certain rate of simple interest per annum, then how much years are required to approximately double the amount at the same annual rate of compound interest ?

OPtion

1) 6
2) 5
3) 6.5
4) 7.5
5) 10
6) 9
7) 12
8) 8
9) 15
10) None of these

Solution

Let rate=R% and principal amount=P, then with simple interest amount after 6 years = P + (PxRx6/100) = 1.48P
⇒ R=8%
With coumpound interest sum after 'n' years = P[1 + 8/100]^n = 2P
(27/25)^n = 2
⇒ n=9
Correct Option 6)

Correct Option: 6 Best Solution (1)