Question 42

A finance company declares that, at a certain compound interest rate, a sum of money deposited by anyone will become 8 times in three years. If the same amount is deposited at the same compound rate of interest, then in how many years will it become 16 times?

Solution

Under compound interest, money will become 8 times in 3 years. Let it takes $$t$$ years to become 16 times.

Substituting values in the formula = $$(x)^{\frac{1}{a}}=(y)^{\frac{1}{b}}$$

=> $$(8)^{\frac{1}{3}}=(16)^{\frac{1}{t}}$$

=> $$(2)^1=(2)^{\frac{4}{t}}$$

Comparing the exponents, we get : $$t=4$$ years

=> Ans - (B)

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