Xiaohua goes from place A to place B, one-third rides a bike and two-thirds takes a bus. Returning from the second place to the first place, three-fifths rode bicycles and two-fifths took buses, resulting in a delay of half an hour. It is known that riding a bike every hour 12km and taking a bus every hour is 30km. Q: How many kilometers is the distance between the two places?

Solution: Take the whole distance as a unit 1.

The difference between the two cycles is 3/5- 1/3=4/ 15.

Speed ratio of cycling and cycling = distance ratio = 30: 12 = 5: 2.

Then the time ratio = 2: 5.

So the time it takes to drive is 2/5 of that of riding a bike.

Then the time required to complete the whole cycle of 4/ 15 by bike = (1/2)/(1-2/5) = 5/6 hours.

Then the time to complete this cycle =(5/6)/(4/ 15)=75/24 hours.

Then the whole journey = 12× 75/24 = 37.5km.

123, it takes Xiao Qiang 3 hours to get from a to b by bike. If he walks 2 kilometers first, the walking speed is 65438+ 0/3 of the riding speed, and he will arrive in 20 minutes. How many kilometers is it between A and B?

20 minutes = 1/3 hours

The speed ratio of walking and cycling =1/3:1=1:3.

Time ratio = 3: 1

Time to walk 2 kilometers = (1/3)/(1-1/3) =1/2 hours.

Walking speed = 2/(1/2) = 4 km/h.

Riding speed = 4× 3 = 12km/h

Distance between Party A and Party B =12× 3 = 36km.

124, a and b are 20km apart. After A rode from A to A for 30 minutes, B rode from B to A, and drove to A at twice the speed of A per hour. The two cars will meet at point C, which is at a distance of point B 12km. What is the speed of both sides?

Solution: speed ratio of Party A and Party B = distance ratio = 1: 2.

Line B is 12km, so line A is 12/2 = 6km.

So A has been driving for 30 minutes = 1/2 hours, and 20- 12-6=2 kilometers.

The speed of a = 2/(1/2) = 4 km/h.

Speed b = 4× 2 = 8 km/h.

125, passengers and trucks leave from Party A and Party B relatively simultaneously. When they meet, the distance ratio between passengers and trucks is 5:4. After the accident, the speed of the truck was 27 kilometers higher than before. The bus was still running at the original speed, and as a result, the two cars arrived at each other's departure station at the same time. It is known that the bus has been driving for 10 hour. How many kilometers is it between A and B?

Solution: When they met, the bus traveled 5/9 of the whole journey, and it took 10×5/9=50/9 hours.

The arrival time in B is 10-50/9=40/9 hours.

The bus and truck arrive at the same time after meeting, so their speed ratio = distance ratio = 4/9: 5/9 = 4: 5 = 5: 25/4.

The proportion of freight cars after speed increase and before speed increase = 25/4: 4 = 25: 16.

Then the original speed of the truck = 27/(25/16-1) = 48 km/h.

Bus speed = 48/(4/5) = 60 km/h.

Distance between Party A and Party B = 60× 10 = 600km.

For reference only, forget it, just practice.