Question

Mohan bought a certain number of note-books for Rs. $600$. He sold $\frac{1}{4}$ of them at $5$ percent loss. At what price should he sell the remaining note-books so as to gain $10\%$ on the whole?

Answer 1

Given, C.P. of the books $=$ Rs. $600$
$\Rightarrow$ C.P. of one $-$ fourth of books $=$ Rs. $\frac{600}{4}=$ Rs. $150$
Loss on one $-$ fourth of books $=5$ $\%$
So, Loss $\%$ $=\frac{C.P.-S.P.}{C.P.}\times 100=5$
$\Rightarrow \frac{150-S.P.}{150}\times 100=5$
$\Rightarrow 150-$ S.P. $=7.5$
$\Rightarrow$ S.P. $=$ Rs. $142.50$
Hence, Selling price of one $-$ fourth of books $=$ Rs. $142.50$
Now, Profit on the whole $\%$ $=\frac{S.P.-C.P.}{C.P.}\times 100=10$
$\Rightarrow \frac{S.P.-600}{600}\times 100=10$
$\Rightarrow$ S.P. $-600=60$
$\Rightarrow$ S.P. $=$ Rs. $660$
Thus, selling price of remaining books $=$ Rs. $660-$ Rs. $142.50=$ Rs. $517.50$.