A man ordered 4 pairs of black socks and some pairs of brown socks. The price of a black socks is double that of a brown pair. Wh…

Question

A man ordered 4 pairs of black socks and some pairs of brown socks. The price of a black socks is double that of a brown pair. While preparing the bill the clerk interchanged the number of black and brown pairs by mistake which increased the bill by 50%. The ratio of the number of black and brown pairs of socks in the original order was:

1. A. 2:1
2. B. 1:4 (Correct answer)
3. C. 1:2
4. D. 4:1

Correct Answer

Option B — 1:4

Detailed Solution & Explanation

The correct answer is 1:4.

Key Points

• Let brown pairs = x, price of brown = P, black = 2P.
• Original bill = 4(2P)+xP = (8+x)P. Swapped bill = x(2P)+4P = (2x+4)P. (2x+4)/(8+x) = 1.5 => 0.5x = 8 => x = 16. Ratio = 4:16 = 1:4.