Everyone can assemble 20(4×3)= 5/3 wheels per hour.
Speed ratio: (11/6): (5/3) =11/0,
Efficiency (headcount) ratio: 10: 1 1,
As a frame is equipped with two wheels, namely 10:22,
There are 128 people, and the frame should be128×10/(10+22) = 40 (people).
The wheel should be 128×22( 10+22)=88 (person).
(2) Question type: trip problem.
Now the speed is (1+0.2)= 1.2 times,
The time is11.2 = 5/6, corresponding to one hour missing.
So the original requirement is 1÷( 1-5/6)=6 (hours).
If the speed is increased by 30% for the second time, it should be 6× (1-1(1+30%) =18/13 (hours).
Actual advance 1 hour, less than planned18/13-1= 5/13 (hour).
From (5/13)/(18/13) = 5/ 18, which is 5/18 of the whole journey.
So the whole journey is 100÷5/ 18=360 (km).
(3) Question type: Train crossing the bridge.
Let the train speed be x (km/s)
The train is chasing a, the train faces b,
As the train length is unchanged, (1/2) (x-15) = (1/3) (x+15).
x=75。
(4) Question type: the hypothetical method to solve the problem.
Xiao Wang's round trip ***7- 1=6 (hours)
Set up east village and west village, level the road for one kilometer, go up the mountain for two kilometers, and go down the mountain for three kilometers.
Conditions: a/4+b/3+c/6+c/3+b/6+a/4=6.
a/2+b/2+c/2=6，
A+b+c= 12。 That is, from the east village to the west village = 12km, and back and forth = 12x2 = 24 (km).
From1/4+1/4 =1/3+1/6 =1/2, ∴a=b=c=4.