Question

Mohit has ₹4000 in his account. He deposits ₹1600 on one scheme at 3% p.a. interest rate and ₹2400 on another scheme at 4% p.a. interest rate. Suggest him a scheme that will yield him as much interest as these two schemes for the principal worth ₹4000.

Answer 1

$\mathrm{We}\mathrm{know},\frac{\mathrm{Interest}}{\mathrm{Principal}}=\frac{\mathrm{Rate}}{100}\Rightarrow \frac{I_1}{1600}=\frac{3}{100}\Rightarrow I_1=₹48\mathrm{Again},\frac{I_2}{2400}=\frac{4}{100}\Rightarrow I_2=₹96\mathrm{Total}\mathrm{interest}=I_1+I_2=₹48+₹96=₹144\mathrm{Now},\mathrm{for}\mathrm{an}\mathrm{equivalent}\mathrm{scheme}:\frac{\mathrm{Interest}}{\mathrm{Principal}}=\frac{\mathrm{Rate}}{100}\Rightarrow \frac{144}{4000}=\frac{\mathrm{Rate}}{100}\Rightarrow \mathrm{Rate}=3.6\%$