A librarian purchased 50 storybooks for his library. But he saw that he could get 14 books more by spending Rs. 76 more but per book average becomes Rs. 1 less. The average price (in Rs.) of each book he bought, was :

A. 15

B. 25

C. 20

D. 10

Answer: Option D

Solution(By Examveda Team)

Let the average price of 1 book = Rs. 1
According to the question,
$$\eqalign{ & \Rightarrow \frac{{50x + 76}}{{\left( {50 + 14} \right)}} = \left( {x - 1} \right) \cr & \Rightarrow \frac{{50x + 76}}{{64}} = x - 1 \cr & \Rightarrow 50x + 76 = 64x - 64 \cr & \Rightarrow 140 = 14x \cr & \Rightarrow x = {\text{Rs}}{\text{.}}\,10 \cr} $$
Therefor average price of 1 book = Rs. 10