The sale price of an article including the sale tax is Rs. 616. The rate of sale tax is 10 %. If the shopkeeper has made a profit of 12%, the cost price of the article is

A Rs 500

B Rs 515

C Rs 550

D Rs 600

Correct Answer: Option A

110% of S.P. = 616
= S.P. = Rs.(616 x 100/110) = Rs.560.
C.P. = Rs (100/112 x 560)
= Rs 500