On selling 18 pens at ₹660, there is a profit equal to the cost price of 4 pens. What is the cost price of one pen (in ₹)?
Answer & explanation
Correct answer: option 3
On selling 18 pens at 660, there is a profit equal to the cost price of 4 pens.
18(sp - cp) = 4cp
9(sp - cp) = 2cp
9sp - 9cp = 2cp
9sp = 11cp … (1)
As we know that selling price of 18 pens is 660.
18sp = 660
3sp = 110 …. (2)
Put Eq.(2) in Eq.(1).
3 ×110 = 11cp
CP = 30