Question

If cost price of 20 books is equal to the selling price of 25 books ,find the gain or loss percent

Answer 1

20 c.p. = 25 s.p.
s.p./c.p. = 20/25 =4/5

(s.p.-c.p.)/c.p. =(4-5)/5 = -1/5
here minus sign indicate loss

for percentage loss we have to multiply by 100
so( 1/5)*100 = 20 %

Answer 2

The loss percent of given is 20%.

Solution :

The cost price of 20 books, let us denote it by Rs. M

So, the Selling Price of 25 books is denoted by Rs. M as well

Therefore, we can say that the cost price of one book is equal to $\frac{M}{20}$and the Selling Price of a single book is $\frac{M}{25}.$

Hence, the profit or loss = S.P. – C.P. $=\frac{M}{225}-\frac{M}{20}=-\frac{1}{100}$

The negative sign indicates loss.

So the loss percentage $=\frac{\ {los} s}{C P} \times 100$

$=\frac{\frac{1}{100}}{\frac{1}{20}} \times 100$

$=20 \%$

Therefore, the loss percent in this transaction is 20%.