The first question really lacks conditions. The first sentence should explain that there are fewer people in workshop A than in workshop C, so this problem can be done!

Suppose we know that there is one less person in workshop A than in workshop C. The answer is as follows:

If the number of people in Workshop B is X, then the number of people in Workshop C is 5/4x. The number of people in workshop a is y.

Equations:

5/4x -y=a

x+y-4=5/4x

You should beg for the next one

The second question is correct, and the answer is as follows:

Let the speed of armored vehicle be x km/h and the distance between a and b be y.

The equation is as follows:

6(60+x)=y

2.5x+350+2.5*60=y

Get: x=40, y=600.

(600- 150)/40+(600- 150)/60+4=22.75

That is to say, it arrives at 22: 45 p.m.