Question

the interest on a sum of money at 6% p.a. for 7 years is equal to twice the interest on
sum of money for 9 years at 5% p.a. Find the ratio of the two sums.
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Answer 1

Answer:

Let the sums be = x and y

For x:

$\sf{S.I. = \frac{PRT}{100}}$

=> $\sf{S.I._{1} = \frac{42x}{100}}$

For y:

$\sf{S.I. = \frac{PRT}{100}}$

=> $\sf{S.I._{2} = \frac{45y}{100}}$

Given that:

$\sf{S.I._{1} = 2(S.I._{2})}$

=> $\sf{\frac{42x}{100} = 2(\frac{45y}{100})}$

=> 42x = 90y

=> $\sf{\frac{x}{y} = \frac{15}{7}}$

Ratio = 15:7

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