A man spends 20% of his monthly salary on his children education, 50% of his salary on food and transport, pays house rent of Rs. 1000, and is left with Rs. 2000; what is his total monthly salary?

Introduction / Context:
This is a standard salary distribution problem that tests the ability to interpret percentage expenses and fixed expenses together. The man spends parts of his salary in percentages on certain categories, pays a fixed rent amount and has a known remaining balance. We must reconstruct his total salary from this information. Such questions are common in the percentage and arithmetic sections of aptitude exams.

Given Data / Assumptions:

• Let the monthly salary be S rupees.
• 20% of S is spent on children education.
• 50% of S is spent on food and transport.
• Rent is Rs. 1000.
• After all these expenses, he is left with Rs. 2000.
• We need to find S.

Concept / Approach:
The total salary must equal the sum of all expenses plus the remaining amount after expenses. The expenses include two percentage based items and one fixed amount. We first express the percentage based expenses in terms of S, then add them along with the fixed rent and the final remaining balance. This sum must equal S. Solving the resulting linear equation gives the value of S. This method is clear and avoids miscounting any part of the salary.

Step-by-Step Solution:
Let monthly salary be S rupees.Spending on children education = 20% of S = 0.20 * S.Spending on food and transport = 50% of S = 0.50 * S.Rent is Rs. 1000.Remaining amount after expenses is Rs. 2000.Total of all outflow and remaining amount must equal S.So equation is 0.20S + 0.50S + 1000 + 2000 = S.Combine like terms: 0.70S + 3000 = S.Rearrange to get S - 0.70S = 3000, so 0.30S = 3000.Hence S = 3000 / 0.30 = 10,000.

Verification / Alternative check:
Check the distribution using S = 10,000. Education spending is 20% of 10,000, which is 2000. Food and transport spending is 50% of 10,000, which is 5000. Rent is 1000. Total expenses are 2000 + 5000 + 1000 = 8000. The remaining amount is 10,000 - 8000 = 2000, which matches the given remaining amount. This confirms that a salary of Rs. 10,000 per month is consistent with all the information given in the question.

Why Other Options Are Wrong:
A salary of Rs. 7000 would not allow both percentage allocations and fixed rent while leaving Rs. 2000, because 70% alone would already be 4900 leaving too little for rent and savings.

Rs. 14,000 or Rs. 20,000 would leave larger remaining amounts than Rs. 2000 once all expenses are calculated, so they cannot satisfy the final condition.

Common Pitfalls:
Some students add the percentage figures incorrectly or neglect the fixed rent when forming the equation. Others mistakenly assume that 20% plus 50% plus the remaining 2000 must directly equal the salary, ignoring the rent. To avoid such errors, always write an explicit equation where salary equals the sum of all expenditures and the final remaining amount, and then solve carefully for S.

Final Answer:
The man total monthly salary is Rs. 10,000.