The distance between the two places is 81 kilometers. A and B ride from the two places at the same time. A rides 10 kilometers per hour, and the two meet after 4.5 hours. How much faster is a than B?

A: the speed of a is 25% faster than that of B

A. The distance between B and a is 105 kilometers. A and B start from a and B at the same time. A's speed is 40 kilometers per hour. They meet one hour and 45 minutes after starting. Then a and B continue to ride forward in their respective directions. Three minutes after they meet, a and C meet, and C overtakes B in C. If a runs at 20 kilometers per hour, B will continue to ride forward, B runs at a speed of 2 kilometers per hour faster than the original speed, and the two start from a and B at the same time. Then a and B meet at C. what's the speed of C?

1 hour 45 minutes = 1.75 hours
B the original speed is: 105 / 1.75-40 = 20 km / h
When a and B meet, the distance a takes is 40 * 1.75 = 70km
3 minutes = 0.05 hours
When a and C meet, the distance between a and a is 40 * (1.75 + 0.05) = 72 km
When a and C meet, the distance between a and B is: (40 + 20) * 0.05 = 3km (this one is useless in the following ways)
When a and C meet, the distance between B and a is 105-20 * (1.75 + 0.05) = 69 km
The distance between point C and point a is: 20 * [105 / (20 + 20 + 2)] = 50 km
The time of B from a and C to C is (69-50) / 20 = 0.95 hours
95 hours is the time for C to catch up with B
And the distance that C pursues B is = the distance between a and a when a and C meet - the distance between C and a
=72-50 = 22 km
The speed of C is: 22 / 0.95 = 23.16 km / h

The distance between AB and a is 40 km. One hour after a bicycle set out from a, a has also set out from a, catching up with a speed of 1.5 times that of a, when it comes to B
A is 20 minutes ahead of A. what's your speed?

If the speed of a is x km / h, the speed of B is 1.5 x km / h
20 minutes = 1 / 3 hour
40/x-40/（1.5x）=1-1/3
The solution is: x = 20
1.5x=30
A speed of 20 km / h, B speed of 30 km / h

A and B are 40 kilometers apart. After a bicycle starts from a, B starts from a and catches up with a speed equivalent to 1.5 times that of A
When catching up with B, a is 20 minutes ahead of B, to find the speed of a and B

Let a's velocity be x, then B's velocity is 1.5x
A walks for 1 hour first, the distance is 1 x, B just starts to chase, B takes time from a to B
be equal to
Time for a to walk the remaining (40-1x) km + 20 minutes
So,
40/（1.5X）=（40-1X）/X + 1/3
The solution of the equation is: x = 20
A's speed is 20 km / h
B's speed is 30 km / h

The distance between the two places is 81 kilometers. A and B ride from the two places at the same time. A rides 10 kilometers per hour, and the two meet after 4.5 hours. How much faster is a than B?