Question

By selling a book for $Rs.258,$ a book seller gains $20\%$. For how much should he sell it to gain $30\%$?

Answer 1

S.P of a book $=Rs..258$
Gain $=20\%$
$\therefore$ C.P of the book $=\frac{S.P\times 100}{100+gain\%}$

$=\frac{258\times 100}{100+20}$

$=\frac{258\times 100}{120}=\frac{258\times 5}{6}=Rs.215$

In second case, gain $=30\%$

$\therefore$ S.P of the book $=\frac{C.P\times (100+gain\%)}{100}$

$=\frac{215\times (100+30)}{100}$

$=\frac{215\times 130}{100}=\frac{27950}{100}=Rs.279.50$