Mr. A spent 25% of his income on food, 10% on children education, 40% of the remaining he spent on entertainment and transport together and 30% on medical.  He is left with an amount of Rs. 7800 after all the expenditure.  What is Mr. A's monthly income?

40,000

Let total income = Rs. P

i) Total expenditure on food and Children education = 25 + 10 = 35%

Thus, ⇒ Remaining amount = P × 65%

ii) Total expenditure on Entertainment, transport and medical = 40 + 30 = 70% of remaining (i.e P × 65%)

Thus,

⇒ Remaining amount = (P × 65%) × 30%

ATQ,

⇒ (P × 65%) × 30% = 7800

⇒ (P × 1%) × 1% = 4

⇒ P = 40,000/-