3x= 120
The solution is x=40.
Later used: 180/40=4.5(h)
* * * Usage: 4.5+3=7.5 (high)
2) Solution: Suppose it takes x hours to process 180 pieces.
120/3= 180/x
Solution: x=4.5
* * * Usage: 3+4.5=7.5 (high)
Xiaohong is in the 25th place.
Xiaohua is in the sixth place.
There are two people: 25-6- 1= 18.