After three successive equal percentage rise in the salary the sum of 100 rupees turned into 140 rupees and 49 paise. Find the percentage rise in the salary.

Explanation:-

We solve it through options. Choosing options for trial depends on mental thought.
100 ==12% up ==>112 ==12% up ==>125.44 ==12% Up ==> 140.49
So, answer is 12%.