Q:

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
  1 : 2
• 2
  4 : 1
• 3
  2 : 1
• 4
  1 : 4