The marked price of a watch was Rs. 720. A man bought the same for Rs. 550.80, after getting two successive discounts, the first 10%. What was the second discount rate ?

A. 12%

B. 14%

C. 15%

D. 18%

Answer: Option C

Solution(By Examveda Team)

Market price of a watch = Rs. 720
After 1^st discount
$$\eqalign{ & {\text{ = 90}}\% {\text{ of 720 }} \cr & {\text{ = }}\frac{{90}}{{100}} \times 720 \cr & = {\text{Rs}}{\text{. 648}} \cr} $$
Cost price of watch = Rs. 550.80
Difference
= 648 - 550.80
= Rs. 97.20
$$\eqalign{ & {{\text{2}}^{{\text{nd}}}}{\text{ discount}} \cr & = \frac{{97.20}}{{648}} \times 100 \cr & = \frac{{9720}}{{648}} \cr & = 15\% \cr} $$