question_answer

(a) Find the compound interest on Rs. 31250 at 8% per annum for \[2\frac{3}{4}\] years.

(b) Mohit bought a CD for Rs. 750 and sold it for Rs. 875. Show that his gain percent is \[16\frac{2}{3}\]%.

Answer:

(a) Since, P = Rs. 31250, n = \[2\frac{3}{4}\]years, R = 8% p.a.

Then,       \[A=31250{{\left( 1+\frac{8}{100} \right)}^{2}}\times \left( 1+\frac{\frac{3}{4}\times 8}{100} \right)\]    \\[=31250\times {{\left( \frac{27}{25} \right)}^{2}}\times \left( \frac{53}{50} \right)\]

\[=31250\times \frac{27}{25}\times \frac{27}{25}\times \frac{53}{50}=Rs.38637\]

Hence,      C.I. \[=\text{ }38637-31250\text{ }=\]Rs. 7387

(b) Since,        C.P. = Rs. 750 and S.P = Rs. 875

C.P. < S.P.

Gain = Rs. (875 - 750) = Rs. 125

Then,                         Gain% \[=\left( \frac{Gain}{C.P.}\times 100 \right)\]

\[=\frac{125}{750}\times 100\]

\[=\frac{50}{3}%=16\frac{2}{3}%\]