The man sold two cows, one at a profit of 10% and the other at a loss of 10%. The selling price for both was Rs. 2600.
As the selling price for both is the same, the profit and loss are due to differences in the buying price.
The cow on which he made a profit of 10% was bought for (2600/1.1). The one he makes a loss of 10% was bought for (2600/0.9)
In all, the cows were bought for
`2600(1/0.9 + 1/1.1) = 5252.52`
They were old for 2*2600 = 5200.
The man makes a loss of (5252/5200)% = 1.01%
The total loss of the man is 1.01%