The profit on first pipe is: 12❌ 20/100= 2.4
Then the actual cost of first pipe is 12➖ 2.4=9.6
The loss on second pipe is:
Then the actual cost of second pipe is: 12➕ 2.4=14.4
Actual cost of two pipes is 24 rupees
Selling price of two pipes = rs 24
Therefore,there is no loss or gain.