Question

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

• A. 4:1
• B. 2:1
• C. 1:4
• D. 1:2

Answer 1

Answer: (C)

1:4

Answer 2

Let he purchase x pairs of brown socks. Price of black socks and brown socks be Rs 2a and Rs a per pair respectively

$\frac{3}{2}(4\times2a+x\times a)=x\times2a+4\times a$

$12a+\frac{3}{2}xa=2xa+4a$

$12+\frac{3}{2}x=2x+4$

$\frac{x}{2}=8$

$\therefore$ Required ratio $=\frac{4}{16}=\frac{1}{4}$
The correct option is (C)