Let the cost price be Rs. 100 Now, the selling price = Rs. 115 New CP. = Rs. 90 New S.P. =
90×125
100
=Rs.112.5 The Difference in S.P. =Rs.(115−112.5) =Rs.2.5 If the difference is Rs. 2.5, the CP. =Rs,100 Therefore, if the difference is Rs. 200, the C.P. =