Antique stamps

Puzzle Question:

My friend collects antique stamps. She purchased two, but found that she needed to raise money urgently. So she sold them for Rs. 8000 each. On one she made 20% and on the other she lost 20%.
How much did she gain or lose in the entire transaction?

Answer --

Solution of Puzzle:

She lost Rs 666.67
Consider the first stamp. She mades 20% on it after selling it for Rs 8000.
So the original price of first stamp is
= (8000 * 100) / 80
= Rs 6666.67
Similarly, consider second stamp. She lost 20% on it after selling it for Rs 8000
So the original price of second stamp is
= (8000 * 100) / 80
= Rs 10000
Total buying price of two stamps
= Rs 6666.67 + Rs 10000
= Rs 16666.67
Total selling price of two stamps
= Rs 8000 + Rs 8000
= Rs 16000
Hence, she lost Rs 666.67

Toughness:

Intermediate