For example:

1 employees need steps * * * to complete all the steps, where step 1, 3,5 is the operation time and step 2,4 is the waiting time.

While waiting for startup in step 2, another mobile phone card loading step 1 can be performed at the same time.

While waiting for filling in step 4, other mobile phone steps 1, 2 and 3 can be performed at the same time.

It takes a person the least time to complete eight mobile phones at the same time and the shortest waiting time, with a total time of 8 10s.

definition

Addition: the operation of combining two numbers into one number.

Subtraction: when two addends and one of them are known, the operation of finding the other addend.

Multiplication: the operation of finding the product of two numbers.

Division: the operation of finding another factor by knowing the product of two factors and one of them.