UPSC Prelims 2024·CSAT·Quantitative Aptitude·Time and Work

A, B, C working independently can do a piece of work in 8, 16 and 12 days respectively. A alone works on Monday, B alone works on Tuesday, C alone works on Wednesday; A alone, again works on Thursday and so on. Consider the following statements: 1. The work will be finished on Thursday. 2. The work will be finished in 10 days. Which of the above statements is/are correct?

Dalvoy logo
Reviewed by Dalvoy
UPSC Civil Services preparation
Last updated 23 May 2026, 3:31 pm IST
  1. A1 OnlyCorrect
  2. B2 Only
  3. CBoth 1 and 2
  4. DNeither 1 nor 2

Explanation

Here's a brief explanation: 1. **Calculate Total Work and Efficiencies:** * A takes 8 days, B takes 16 days, C takes 12 days. * The Least Common Multiple (LCM) of 8, 16, 12 is 48 units. This is our total work. * A's efficiency = 48/8 = 6 units/day * B's efficiency = 48/16 = 3 units/day * C's efficiency = 48/12 = 4 units/day 2. **Track Work Done Day by Day:** * Day 1 (Monday, A): 6 units. Total = 6 * Day 2 (Tuesday, B): 3 units. Total = 9 * Day 3 (Wednesday, C): 4 units. Total = 13 * Day 4 (Thursday, A): 6 units. Total = 19 * Day 5 (Friday, B): 3 units. Total = 22 * Day 6 (Saturday, C): 4 units. Total = 26 * Day 7 (Sunday, A): 6 units. Total = 32 * Day 8 (Monday, B): 3 units. Total = 35 * Day 9 (Tuesday, C): 4 units. Total = 39 Remaining work = 48 - 39 = 9 units. * Day 10 (Wednesday, A): A works and does 6 units. Total = 39 + 6 = 45 units. * Remaining work = 9 - 6 = 3 units. * Day 11 (Thursday, B): B works and does 3 units. Total = 45 + 3 = 48 units. 3. **Evaluate Statements:** * **Statement 1: The work will be finished on Thursday.** This is correct. The work is completed on Day 11, which is a Thursday. * **Statement 2: The work will be finished in 10 days.** This is incorrect. The work is finished on Day 11. Therefore, only statement 1 is correct. The final answer is A) 1 Only.
Quantitative Aptitude: A, B, C working independently can do a piece of work in 8, 16 and 12 days respectively. A alone works on Monday, B alone

Related questions

More UPSC Prelims practice from the same subject and topic.