Engineering problems mainly involve the basic quantitative relationship: total work = working efficiency × working time.

For example, homework A can be completed in 10 days, and homework B can be completed in 15 days. How many days can two people cooperate to complete it?

Analysis: A job as a whole is 1, so the workload can be counted as 1. The so-called work efficiency is completed in unit time.

The time unit we use is "day", and 1 day is a unit, so the work efficiency of A is110.

The work efficiency of B is115.

If the time required for two people to cooperate is required, the working efficiency of two people to cooperate first is as follows:110+115 =1/6.

, and then according to the basic quantitative relationship, it is concluded that the required time = workload ÷ work efficiency.

1÷ 1/6=6 (days)

That's two people.

Cooperation takes six days.

In engineering problems, we can adopt this method.