In an army camp, 300 soldiers had provisions for 13 days. If 40 of them are transferred to the other camp, how long will the provisions last?

Answer

To solve the problem step by step, we will use the unitary method.

**Step 1: Calculate the total provisions in soldier-days.**
- We know that 300 soldiers have provisions for 13 days.
- Therefore, the total provisions in soldier-days can be calculated as:
\[ \text{Total provisions} = \text{Number of soldiers} \times \text{Number of days} = 300 \times 13 = 3900 \text{ soldier-days} \]

**Step 2: Determine the number of soldiers remaining after the transfer.**
- 40 soldiers are transferred to another camp.
- The number of soldiers remaining is:
\[ \text{Remaining soldiers} = 300 - 40 = 260 \text{ soldiers} \]

**Step 3: Calculate how long the provisions will last for the remaining soldiers.**
- We already calculated the total provisions as 3900 soldier-days.
- Now, we need to find out how many days the provisions will last for 260 soldiers:
\[ \text{Number of days provisions will last} = \frac{\text{Total provisions}}{\text{Remaining soldiers}} = \frac{3900}{260} \]
- Performing the division:
\[ \frac{3900}{260} = 15 \text{ days} \]

**Final Answer:**
The provisions will last for **15 days** after 40 soldiers are transferred.

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