Question

Mr hari spends 66% of his salary on his family . 20% of the remaining he gives to a trust for charity and is left with 12240 RS . what is the total salary of Mr hari ?? and how much amount does he give to the trust ?

Answer 1

Let  Salary = S
Spent on family = 0.66 * S
Remaining = S - 0.66 S =  0.34 * S  
given to the trust =  0.20 * 0.34 *S = 0.068 * S

What is left = 0.80 * (0.34 * S)  =  0.272  S

               0.272 * S = 12, 240 Rs
                 S =  Rs 45, 000

given to trust =  0.068 * S =  Rs 3, 060

Answer 2

Let the Salary = x
Spent on family = 0.66x
Remaining = x - 0.66x =  0.34x  
given to the trust =  0.20 * 0.34x = 0.068 x

What is left = 0.80(0.34x)  =  0.272x

               0.272x = 12, 240 Rs
                 x =  Rs 45, 000

given to trust =  0.068x =  Rs 3, 060