Question

If the cost price of 6 pencils is equal to the selling price of 5 pencils, then the gain percent is

(a) 10%
(b) 20%
(c) 15%
(d) 25%

Answer 1

Let the cost price of one pencil be ₹1.
Then, CP of 5 pencils = ₹5
and SP of 5 pencils = ₹6 (∵ SP of 5 pencils = CP of 6 pencils)

Therfore, SP is more than CP.

So, Profit = SP − CP
= ₹6 − ₹5
= ₹1

$$\begin{gathered} \mathrm{Gain}\mathrm{percent}=\frac{\mathrm{Profit}}{\mathrm{CP}}\times 100 \\ =\frac{1}{5}\times 100 \\ =20\% \end{gathered}$$

Hence, the correct option is (b).