20 people build a road, which is planned to be completed in 15 days. After 3-3 days of construction, five people will be taken out to plant trees, and the rest will continue to build roads. If everyone's work efficiency remains the same, how many days will it actually take to complete this road?

Answer and analysis:

When you encounter such a problem, you have to assume that a person does a job a day.

Then the total number is 1× 20× 15 = 300-20 people 15 days ***300 copies.

If actual days are required, actual days =3+ remaining days.

So we must first find the remaining days, and the remaining days = remaining copies/number of people.

The rest of the day's work was completed by 20-5= 15 people.

Remaining parts = total parts 300- dried parts

I did it for three days, and 20 people did it every day for three days, so I made 1×3×20=60 copies.

300-60= 240 copies left.

Days remaining =240/ 15= 16 days

Actual days = 16+3= 19 days.

This process assumes that everyone does a job.

1×20× 15=300 copies-total

1×3×20=60 copies-60 copies have been made.

300-60=240 copies-the remaining copies.

240/(20-5)= 16 days-remaining days.

16+3= 19 days-actual days.