To solve this problem, we can use the concept of "man-days." The idea is that the amount of work done is proportional to both the number of workers and the number of days they work.

Step 1: Calculate the total amount of work in man-days.

• If 15 men can reap the crops in 28 days, the total amount of work is: $\text{Total work} = 15 \text{ men} \times 28 \text{ days} = 420 \text{ man-days}$

Step 2: Determine the number of days required for 5 men to complete the work.

• We know the total work is 420 man-days, and we want to find out how many days $x$ it will take for 5 men to complete this work: $5 \text{ men} \times x \text{ days} = 420 \text{ man-days}$

Step 3: Solve for $x$.

$x = \frac{420 \text{ man-days}}{5 \text{ men}} = 84 \text{ days}$

So, 5 men will take 84 days to reap the crops.

Would you like further details on this solution, or do you have any other questions?

Related Questions:

1. If 10 men can complete a task in 15 days, how many men would be needed to complete the same task in 5 days?
2. How many days will it take for 7 men to complete a task that 21 men can finish in 10 days?
3. If 20 workers can dig a trench in 6 days, how long will it take for 8 workers to dig the same trench?
4. If 30 men can paint a house in 12 days, how many men are required to paint the house in 8 days?
5. How long will it take for 12 men to complete a job if 6 men can do it in 24 days?

Tip:

When dealing with work problems, remember that the total work done is typically measured in "man-days" or "man-hours," depending on the problem. This concept allows you to scale the number of workers and days accordingly.