2. Solution: Let there be X people in the first workshop and Y people in the third workshop.
x
=y- 12
→
x+y+3/4
y
=538
The solution of the equation is
x= 188
; y=200
538- 188-200= 150 (person)
Answer: There are 0/88 people in Workshop 1, 0/50 people in Workshop 2 and 200 people in Workshop 3.
3. Party A, Party B and Party C plant 24+30+32=86 trees every day.
; AB * * * 900+1250 = 2150 trees.
; It takes at least 2 150/86=25 days.
A can plant 24*25=600 trees in 25 days.
; So we need B to plant trees within A (900-600)/30= 10 days.
Answer: on the eleventh day, B changed from A to B.
4. Party A's work efficiency =114, Party B's work efficiency = 1/20, and cooperative work efficiency = 17/ 140. Alternate work of Party A and Party B is equivalent to cooperation of Party A and Party B 1 hour. So 1 divided by17/140 =140/17 = 8+4/ 17, so we worked together for 8 hours, so the remaining 4//kloc-0.
+
three
+
5/ 17
hour
5. When the vehicle speed is reduced to 10%, the speed is 9/ 10, so the time spent is 10/9, which is known to be longer than the original time 1h, so the original time spent is1÷ (/kloc.
Assuming that the second start speed is increased by 20% all the way, that is, the speed is 12/ 10, then the time taken should be 10/ 12, that is, 9.
*
10/ 12
=
7.5(h), 9-7.5 years earlier than the original time.
=
1.5(h)； It is known that the speed is increased after driving 180km, which is only 1h earlier than the original speed, that is, the distance of driving 180km offsets the advance of 0.5h, accounting for 0.5÷ 1.5 of the total advance.
=
1/3, so 180km also accounts for 1/3 of the total distance, so the total distance between AB is 180÷ 1/3.
=
540 kilometers.