Party A completes it in one day, Party B completes it in b days, Party A and Party B cooperate for c days, leaving d days ... If the assumed person is A: [1(a+b)] * C+(1/a) * D =1; If the hypothetical person is b: [1(a+b)] * c+(1/b) * d =1.

Workload = working efficiency × working time = workload ÷ working time

Working hours = workload ÷ work efficiency = sum of workload to complete a task = total workload = 1

The concept of engineering problems

It is the focus of mathematics application problem teaching in primary and secondary schools, the extension and supplement of fractional application problem, and an important tool to cultivate students' logical thinking ability. It is a powerful penetration of the idea of one-to-one correspondence of functions in application problems. The engineering problem is also the difficulty of the textbook.

Basic characteristics of engineering problems

Let the total workload be "1" and the work efficiency be = 1/ times.

Basic methods of engineering problems

Arithmetic method, proportional method, equation method.

The basic idea of engineering problems:

Do it together, do it together.