List price of a book is Rs. 100. A dealer sells three such books for Rs. 274.50 after allowing discount at a certain rate, find the rate of discount = ?

Answer: Option C

Given,
= MRP of book = Rs. 100
= Selling price of 3 books = Rs. 274.50
= Selling price of 1 book = Rs. 91.50
Discount on each book
= 100 - 91.50 = Rs. 8.50
Therefore discount %
$$\begin{array}{rl}& =\frac{8.50}{100}\times 100\%\\ & =8.50\%\end{array}$$