Question

Gopi invests Rs 2500for 5 years . he also invests Rs 3500 for 3 at the rate of 3%higher than the first rate of interest. The total Interest he earns from these together is rs 2155.Find the two rates
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Answer 1

Let the rate of interest be x (for first case)

(for second case) the rate of interest = x+3

Now,

Si for case 1 =$\sf{\frac{2500 \times 5 \times x}{100 } = 125x}$

Si for case 2=$\sf{\frac{3500 \times 3 \times (x + 3)}{100} = \frac{10500(x + 3)}{100} = 105x + 315}$

A.T.Q,

SI 1 + SI 2 =2155

So,

125x + 105x + 315 = 2155

230x = 2155 - 315 = 1840

$\sf{x =\frac{1840}{230} = 8}$

x = 8%

Therefore,

$\implies\begin{\boxed{\sf{Rate\: of\: interest\: in\: case \:1 = 8\%}}}$

$\implies{\boxed{\sf{\purple{Rate\: of\: interest\: in \:case \:2 = 8 + 3 = 11\%}}}$