Question

If the selling price of 10 pens is the same as the cost price of 12 pens then gain per cent is

(a) 2 %

(b) 12 %

(c) 20 %

(d) 25 %

Answer 1

Answer : (c)

SP of 10 pens = CP of 12 pens = Rs. 100 (suppose)

$\therefore$ SP of 1 pen $=Rs.\frac{100}{10}=Rs.10$

and CP of 1 pen $=Rs.\frac{100}{12}=Rs.\frac{25}{3}$

Gain = SP - CP = Rs. $10-\frac{25}{3}$

$=Rs.\frac{5}{3}$

Gain % $=\frac{Totalgain\times 100}{CP}=\frac{5\times 100\times 3}{3\times 25}=20\%$