1. Gain or Loss percent
by Analysis

2. Recap When S.P>C.P there is profit
Profit = Selling price – Cost price
Selling price = Cost price + Profit
Cost price = Selling price – Profit
When S.P<C.P there is Loss
Loss = Cost price – Selling price
Selling price = Cost price - Loss
Cost price = Selling price + Loss

3. Given : C.P. of 11 pens = S.P. of 10 pens = Rs 10x
Example 1:- The cost price of 11 pens is equal to the selling price of 10 pens. Find the loss or gain percent.
Solution
Let S.P. of each pen be x.
Then S.P. of 10 pens = Rs 10x
Then S.P. of 11 pens = Rs 11x
Given : C.P. of 11 pens = S.P. of 10 pens = Rs 10x
Here, S.P. > C.P. therefore profit
∴ Profit = S.P. – C.P.
= 11x – 10x = x
Ans: Gain percent is 10%

4. Given : S.P. of the first wrist watch = Rs 594, Gain% = 10%
Example 2: A man sells two wrist watches at Rs 594 each. On one he gains 10%
and on the other he loses 10%. Find his gain or loss percent on the whole.
Solution
Given : S.P. of the first wrist watch = Rs 594, Gain% = 10%
∴ C.P. of the first wrist watch
Similarly, C.P. of the second watch on which he loses 10% is

5. Total C.P. of the two watches = 540 + 660 = Rs 1,200.
To say whether there was an overall Profit or Loss, we need to find the
combined C.P. and S.P.
Total C.P. of the two watches = = Rs 1,200.
Total S.P. of the two watches = = Rs 1,188.
Net Loss = total C.P – Total S.P
Net Loss = 1,200 – 1,188 = Rs 12.
Ans: Loss percent on the whole is 1%

6. Try these
The cost price of 14 pens is equal to the selling price of 10
pens. Find the loss or gain percent.
A man sells two bags at Rs each. On one he gains 50%
and on the other he loses 50%. Find his gain or loss percent
on the whole.