When car A reaches the finish line, car B is 40× 1 = 40km away from the finish line.
Car a travels 40 kilometers more than car B.
Then the time for a car to reach the finish line is 40/(50-40) = 4 hours.
Distance between the two places = 40× 5 = 200km.
16. Two cars leave from Party A and Party B at the same time and meet at 4 o'clock. The speed of the local train is three-fifths of that of the express train. When we met, the express train traveled 80 kilometers more than the local train. How far is the distance between the two places?
Solution: The speed ratio of the express train and the local train = 1: 3/5 = 5: 3.
When they met, the express train traveled 5/8 of the whole journey.
The local train covered three-eighths of the whole journey.
Then the whole journey = 80/(5/8-3/8) = 320km.
17, Party A and Party B set out from A and B respectively at the same time and walked towards each other. Party A walks 100 meters per minute, and Party B walks 120 meters per minute. Two hours later, they were150m apart. What is the shortest distance between a and b? What is the longest distance?
Solution: The shortest distance is that we have seen it, and the longest distance is that we have not seen it.
Speed sum =100+120 = 220m/min.
2 hours = 120 minutes
The shortest distance = 220×120-150 = 26400-150 = 26250m.
The farthest distance = 220×120+150 = 26400+150 = 26550m.
18, and the distance between Party A and Party B180km. A car is scheduled to travel from A to B for 4 hours, but it actually travels 5 kilometers per hour more than originally planned, so it can arrive a few hours earlier than originally planned.
Solution:
Original speed =180/4 = 45 km/h.
Actual speed = 45+5 = 50km/h.
Actual time = 180/50=3.6 hours.
4-3.6= 0.4 hours in advance
19, A and B start from AB at the same time. When they met, the distance they walked was 4: 3. After meeting, B is faster than A by 12km per hour, and A still keeps the original speed. As a result, the two cars arrived at the destination at the same time. It is known that B traveled 12 hours.
Solution: Let the speeds of Party A and Party B be 4a km/h and 3a km/h respectively.
therefore
4a× 12×(3/7)/(3a)+4a× 12×(4/7)/(4a+ 12)= 12
4/7+ 16a/7(4a+ 12)= 1
16a+48+ 16a=28a+84
4a=36
a=9
A =4×9=36 km/h speed.
AB distance = 36× 12 = 432km.
Arithmetic method:
Time after meeting = 12×3/7=36/7 hours.
Speed 12km, linear speed per second 12x36/7 = 432/7km.
When we met, A was more than B. 1/7.
Then the whole journey = (432/7)/( 1/7) = 432km.
20. Two cars, A and B, drive in opposite directions from two places 325 kilometers apart at the same time. The speed of A car is 52 kilometers per hour, and the speed of B car is 65438+0.5 times that of A car. When will the cars meet?
Solution: velocity b = 52×1.5 = 78 km/h.
325/(52+78)=325/ 130=2.5.
2 1, two cars, Party A and Party B, start from A and B at the same time and drive in opposite directions. A travels 80 kilometers per hour, and B travels 10% of the whole journey per hour. When B travels to 5/8 of the whole journey, Party A can reach B through 65438+ 0/6 of the whole journey. How many kilometers is it between A and B?
Solution: 5/8 of the whole journey of Bank B = (5/8)/(110) = 25/4 hours.
AB distance = (80× 25/4)/(1-kloc-0//6) = 500× 6/5 = 600 km.
22. Two cars of Party A and Party B leave the two places relatively at the same time. Car A travels 40 kilometers per hour and car B travels 45 kilometers per hour. When the two cars meet, the second car is 20 kilometers away from the midpoint. How many kilometers are the two places apart?
Solution: The speed ratio of A and B = 40: 45 = 8: 9.
Distance ratio between Party A and Party B = 8: 9.
When meeting, Party B made the whole journey of 9/ 17.
Then the distance between the two places = 20/(9/17-1/2) = 20/(1/34) = 680km.
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