Question

a shopkeeper marks his good 30% above the cost price and gives a discount of 15% on the market price what gain% does he make

Answer 1

Hello dear!!

Let the C.P be x. 

$30\% \: on \: c.p \: = 30\% \: of \: x$

$= \frac{30}{100} \times x$
$= \frac{3x}{10}$
$MP = x + \frac{3 x }{10}$
$= \frac{10x + 3x}{10} \\ = \frac{13 x}{10}$
$Discount=15\% \: of\ \: \frac{13x}{10}$

$= \frac{15}{100} \times \frac{13x}{10}$

$\frac{39x}{200}$

$s.p= M.P- Discount$

$\frac{13x}{10} - \frac{39x}{200}$

$= \frac{260x - 39x}{200}$

$\frac{221x}{200}$

$gain = S.p- c.p$

= 221x - 200x/200 

= 21x/200 

Gain % = gain × c.p /100 

= 21x × 100/200*x 

= 21/2%

=10.5%