Question

A man sold two steel chairs for rs. 500 each. on one, he gains 20% and on other, he loses 12%. how much does he gain or lose in the whole transaction? 1.5% gain 2% gain 1.5% loss 2% loss

Answer 1

For the first chair:
500 = 120% of ? (100% + 20% profit)
Divide each side by 1.20
The chair initially cost 416.67
.
For the second chair:
500 = 88% of ? (100% - 12% loss)
Divide each side by 0.88
The chair initially cost 568.18
.
How much did he pay altogether for the chairs?
416.68 + 568.18 = 984.86
He sold them for 1000
His net profit then is 1000 - 984.86, or 15.14
.
What % of 984.86 is 15.14?
Divide by 984.86 to get 1.54% profit
.
At least he's in the black :-) 
You answer is 1.5%

Answer 2

Let the price of the first chair be x, he gains 20%. Therefore, x + (20/100 * x) = ₹500.
On solving, we get 1.2x = ₹500 ⇒ x = ₹416.67.
Let the price of the second chair be y, he loses 12%. Therefore, y - (12/100 * y) = ₹500.
On solving, we get 0.88y = ₹500 ⇒ y = ₹568.18.
His total income was ₹1000. His net profit/loss was 1000 - (416.67+568.18) = ₹15.15
Therefore, we have net profit = 15.15/1000 * 100 = 1.515% = 1.5%