If on a marked price, the difference of selling prices with a discount of 42% and two successive discounts of 15% and 10% is Rs. 185, then the marked price is:

Let the marked price be Rs. x.
Case 1: Single discount of 42%

Selling Price
1
​
=x×(100−42)%=0.58x
Case 2: Two successive discounts of 15% and 10%
The single equivalent discount for two successive discounts of a% and b% is:

Equivalent Discount=a+b−
100
ab
​

Equivalent Discount=15+10−
100
15×10
​
=25−1.5=23.5%
Selling Price
2
​
=x×(100−23.5)%=0.765x
Given that the difference between the selling prices is Rs. 185:

0.765x−0.58x=185
0.185x=185
x=
0.185
185
​
=1000
Thus, the marked price is Rs. 1,000.