A man spends Rs. 3,300/-. This was 75% of his monthly income. His monthly income is ____.

Man spends 3300 rupees which is equal to 75% of his monthly income.
This entails that man used 3/4 of income of his income and 25% of his income is remaining.
So, divide 3300/3=1100
multiply 1100 x 4 = 4400 (Answer)