UPSC Prelims 2013·CSAT·Quantitative Aptitude·Time and Work

In a garrison, there was food for 1000 soldiers for one month. After 10 days, 1000 more soldiers joined the garrison. How long would the soldiers be able to carry on with the remaining food?

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Last updated 23 May 2026, 3:31 pm IST
  1. A25 days
  2. B20 days
  3. C15 days
  4. D10 daysCorrect

Explanation

The garrison initially had food for 1000 soldiers for 30 days (assuming one month = 30 days). Total food units = 1000 soldiers * 30 days = 30000 soldier-days. After 10 days, food consumed = 1000 soldiers * 10 days = 10000 soldier-days. Remaining food units = Total food units - Food consumed Remaining food units = 30000 - 10000 = 20000 soldier-days. Now, 1000 more soldiers joined, so the total number of soldiers becomes 1000 + 1000 = 2000 soldiers. The remaining food will last for = Remaining food units / New total soldiers Days = 20000 soldier-days / 2000 soldiers = 10 days. Therefore, the soldiers would be able to carry on with the remaining food for 10 days. Analyzing the options: A) 25 days: Incorrect. This would imply the food lasts much longer than calculated. B) 20 days: Incorrect. This would be the answer if no new soldiers joined (20000 / 1000 = 20 days). C) 15 days: Incorrect. This does not match the calculation. D) 10 days: Correct, as per the calculation. The final answer is D.
Quantitative Aptitude: In a garrison, there was food for 1000 soldiers for one month. After 10 days, 1000 more soldiers joined the garrison. Ho
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