1. Suppose the distance between the trams is 1, V1 is the speed of Xiao Wang, and V2 is the speed of Xiao Zhang. Then
V1+V car=1/9 V2+V car=1/8 2V car=1/6 V car=1/12
V1=1/9-1 /12=1/36 V2=1/24
S total=45×(1/12)=15/4 (15/4)÷(1/36+1/24)=54 points
2.400÷(400-360)=10
(10000-400×10)÷(400+18)≈14.3540
(10000- 360× 10)÷(360×5/4)≈14.2222
∴B comes first
The second question: B reaches the finish line first When the game started for 10 minutes in, A. took the lead. When B makes a complete circle, A has traveled 4,000 meters. After B has traveled 3,600 meters, A's speed is 418 m/min. The speed of B is 450 m/min. B can catch up with A in 12.5 minutes. can't finish the race in 12.5 minutes. The person who travels 6,000 m downhill, so B reaches the end point first.
The third question assumes that A's original speed is x and the return timeour is t, then the original speed of B is the speed is x+2
xt+( x+2)(24-t)=200
(x+2 )t+x(24-t)=200
Solve for x=14
So the original speed of A is 14 m/s
For the fourth question, suppose the speed of fast A is x, the speed of slow B is y, and the entire distance is m, then
12x =12y+m
4x+4y=m
Solving for x=2y means the time to run there is 12 minutes (they intersect once every 12 minutes), then x runs once. The time is 6 minutes
A and B are the two starting points of the tram There is. a tram every 12 minutes. The tram travels at 25 kilometers per hour. I would like to ask: (1) If Xiao Ming takes a tram from point A
Over the same distance, it takes 6 minutes for two trams to travel relative to each other, 8 minutes for the tram to travel from Mingming, and 9 minutes for the tram to travel from Lingling Minutes.
Let this distance be s, the speed of the cart be d, the speed of Mingming be m and the speed. of Lingling is L
Then
s/(d+ d)=6 ①
s/(d+m)=8 ②
< p> s/(d+l) = 9 ③①/② Obtain m/d = 1/4
①/③ Obtain l/d = 1/6
Therefore, the combined speed of Lingling and Mingming is faster than the speed of the tram.
1/4+1/6=5/12
By Therefore, the time required for the two to meet is 12/5 times the entire tram ride
=45*12/5 = 108 minutes.
Olympiad Problem of mathematics (Part 6) Experts, please help~~< /h3>
（1）25×
| 12 |
| 60 |
=5÷50× 60
=6 (minutes)
Answer: He will see a tram coming towards him every 6 minutes.
(2) 25×
| 12 |
| 60 |
=5÷30 ×60
=10 (minutes)
25×
| 12 |
| 60 |