UPSC Prelims 2017·CSAT·Quantitative Aptitude·Arithmetic

The monthly incomes of X and Y are in the ratio of 4:3 and their monthly expenses are in the ratio of 3:2. However, each saves Rs. 6,000 per month. What is their total monthly income?

Dalvoy logo
Reviewed by Dalvoy
UPSC Civil Services preparation
Last updated 23 May 2026, 3:31 pm IST
  1. ARs. 28,000
  2. BRs. 42,000Correct
  3. CRs. 56,000
  4. DRs. 84,000

Explanation

Let X's income be 4k and Y's income be 3k. Let X's expense be 3m and Y's expense be 2m. Since Income - Expense = Savings, we can set up two equations: 1) For X: 4k - 3m = 6000 2) For Y: 3k - 2m = 6000 To solve for k, we can eliminate m. Multiply equation (1) by 2: 8k - 6m = 12000 Multiply equation (2) by 3: 9k - 6m = 18000 Subtract the first modified equation from the second modified equation: (9k - 6m) - (8k - 6m) = 18000 - 12000 9k - 8k = 6000 k = 6000 The total monthly income is the sum of X's and Y's incomes: Total income = 4k + 3k = 7k Total income = 7 * 6000 = Rs. 42,000 Therefore, option B is correct. Analysis of options: A) Rs. 28,000: This would be X's income (4k) if k=7000, or 7k if k=4000. Incorrect. B) Rs. 42,000: This matches our calculated total income (7k where k=6000). Correct. C) Rs. 56,000: This would be 8k. Incorrect. D) Rs. 84,000: This would be 12k. Incorrect.
Quantitative Aptitude: The monthly incomes of X and Y are in the ratio of 4:3 and their monthly expenses are in the ratio of 3:2. However, each
ShareWhatsAppXTelegram

Related questions

More UPSC Prelims practice from the same subject and topic.