Question

Mark (✓) against the correct answer
A sum of Rs 600 amounts of Rs 720 in 4 years. What will it amount to if the rate of interest is increased by 2%?

(a) Rs 724
(b) Rs 648
(c) Rs 768
(d) Rs 792

Answer 1

(c) Rs. 768

$$\begin{gathered} \begin{array}{l}\text{Let the rate be}\mathit{\text{R}}\text{\%.}\end{array} \\ \mathrm{S}.\mathrm{I}.=\mathrm{A}-\mathrm{P} \\ =720-600 \\ =\mathrm{Rs}.120 \\ T\mathrm{ime}=4\mathrm{years} \\ R=\frac{100\times SI}{P\times T} \\ R=\frac{100\times 120}{600\times 4} \\ =5 \\ \mathrm{Rate}\mathrm{of}\mathrm{interest}=5\% \\ \mathrm{Now},\mathrm{R}=(5+2)\%=7\% \\ S.I.=\frac{\mathrm{P}\times \mathrm{R}\times \mathrm{T}}{100} \\ =\frac{600\times 7\times 4}{100} \\ =\mathrm{Rs}.168 \\ \mathrm{Amount}=\mathrm{SI}+\mathrm{P} \\ =600+168 \\ =\mathrm{Rs}.768 \end{gathered}$$