250/100 * 1400 - x/100 * 1680=1580
3500 - x/100 * 1680 = 1580
3500 - x * 1680 = 1580 * 100
3500 - x * 1680 = 158000
-x*1680 = 158000 - 3500
- x * 1680 = 154500
- x = 154500 / 1680
x = 92
I think we need to solve this sum in this method. but am not sure.
kindly let me know.