Christy donated 10% of his income to an orphanage and deposited 20% of the remainder in his bank. If he has now Rs. 7200 left, what is his income :

Answer: Option A

Total income = 100x
10% deposit to orphange = 100x of 10% = 10x
Remain income 90x
Now 20% deposit to bank = 90x of 20% = 18x
Reamin income 90x - 18x = 72x
According to question
72x = 7200
⇒ x = $$\frac{7200}{72}$$ = 100
Income of Christy = 100 × 100 = 10000