The sale price of a trolley bag including the sale tax is Rs. 560. The rate of sale tax is 12% . If the shopkeeper has made a profit of 25%, the cost price of the trolley bag is:
Choose the correct choice from the following choices.
A) rs 1000
B) rs 900
C) rs 400
D) rs 600
E) none of these

Rationale: "explanation : 112 % of s . p . = 560 s . p . = rs . ( 560 x 100 / 112 ) = rs . 500 . c . p . = rs ( 100 / 125 x 500 ) = rs 400 answer : c"
Answer: C