Question

A vegetable seller on selling 20 kg potatoes earns a profit equal to the cost price of 5 kg potatoes. Find his profit percentage.

Answer 1

Let x be the C.P. of 1 kg of potatoes.
Thus, the C.P of 20kg of potatoes is 20x.
The profit in selling 20kg of potatoes is 5x.
Thus the profit is 5x. 
Profit%=Profit/CP*100%
=25%

Answer 2

Let Cost price of 1 kg potatoes be Rs. x
.·. Cost price of 20 kg potatoes is Rs. 20x
.·. Profit gained by selling 20 kg potatoes is Rs. 5x
Then, Profit made is Rs. 5x

Profit % =$\frac{Profit}{C.P.} * 100$
 
              = ( $\frac{5x}{20x}*100$ ) %
 
              = 25% (Answer)

Thus, the profit percent is 25%.