Question

The SI on a sum of money for $3$ years is Rs.$240$ and the CI on the sum at the same rate for $2$ years is Rs. $170$. The rate $\%$ p.a. is:

• A. $16\%$
• B. $8\%$
• C. $12\frac{1}{2}\%$
• D. $8\frac{1}{3}\%$

Answer 1

Answer: (C)

$12\frac{1}{2}\%$

S.I. for 1 year$=\frac{240}{3}=Rs.80=$ C.I. for 1 year

C.I. for 2 years $=Rs.170$

C.I. for 1 year+C.I for 2nd year $=Rs.170$

C.I. for 2nd year$=170-80=Rs.90$

$\therefore$ Interest on Rs. $80$ for one year$=90-80=Rs.10$

$\therefore$ Rate of interest$=\frac{10}{80}\times 100=12\frac{1}{2}\%$