A garrison of 2000 men has provision of ration for 66 days. At the end of a fortnight, reinforcement arrives and it is found that ration will last only for 20 days more. The strength of the reinforcement is
Aptitude
Chain Rule
Difficulty: Medium
Choose an option
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A2000
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B2200
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C2600
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D3200
Answer
Correct Answer: 3200
Explanation
### Concept & Remaining Provisions
The total quantity of remaining ration is constant regardless of how many people consume it. We equate the (original men $\times$ remaining scheduled days) to (new total men $\times$ actual days it lasted).
$$ M_1 \times D_{remaining} = M_{total} \times D_{new} $$
### Step-by-Step Solution
* **Initial state:** 2000 men have rations for 66 days.
* **Time passed:** A fortnight is 14 days. After 14 days, the remaining food would last the 2000 men for $66 - 14 = 52$ days.
* **Remaining man-days:** $2000 \times 52$.
* **New scenario:** Let the total number of men after reinforcement be $M_{total}$. The remaining food lasts for 20 days.
* **Equation:** $2000 \times 52 = M_{total} \times 20$
* $M_{total} = \frac{2000 \times 52}{20} = 100 \times 52 = 5200$ men.
* **Finding Reinforcement:** The strength of the reinforcement is the difference between the total men and the original men.
* Reinforcement $= 5200 - 2000 = 3200$ men.
### Exam Strategy & Shortcut
Instead of finding total men first, you can directly find the reinforcement ($R$). The food meant for 2000 men for $(52 - 20) = 32$ days is eaten by the reinforcement ($R$) in 20 days. $2000 \times 32 = R \times 20 \implies R = 3200$.
### Common Pitfall
Forgetting what a "fortnight" means (14 days) or solving for the total number of men (5200) and incorrectly choosing an option, forgetting to subtract the initial 2000 men to find the reinforcement.
### Final Answer
Therefore, the correct answer is **3200**.