17 copies of a book were sold for Rs.1800/- thereby gaining cost price of 3 copies. The cost price of a copy is:
Answer & explanation
Correct answer: option 2
Profit = S.P. of 17 - C.P. of 17
C.P. of 3 = S.P. of 17 - C.P. of 17
C.P. of 20 = S.P. of 17
C.P. : S.P.
17 : 20
⇓ ⇓ × 90
⇓ × 90 1800 (given)
(17× 90)
C.P of 17 articles = 17× 90
C.P. of each article = Rs.90/-