a. B is 72 kilometers away from each other. A starts from a to B by bicycle at a speed of 5 meters per second. When a starts for 2 hours, B starts from a by motorcycle to catch up with a If the speed of the motorcycle is 48 km / h, then B will catch up with a at the distance from B,

a. B is 72 kilometers away from each other. A starts from a to B by bicycle at a speed of 5 meters per second. When a starts for 2 hours, B starts from a by motorcycle to catch up with a If the speed of the motorcycle is 48 km / h, then B will catch up with a at the distance from B,

Bicycle speed conversion, is 18 kilometers per hour
Suppose that Party A leaves for X hours and is overtaken by Party B
18X=48（X-2）
X=3.2
At this time, a walked 57.6 kilometers
So the distance from B is 72-57.6 = 14.4

As shown in the figure, a and B are 50 kilometers apart. A starts from a to B by bicycle at 1 pm on a certain day, and B also starts from a to B by motorcycle in the afternoon of the same day. PQR and Mn in the figure respectively show the relationship between s driven by a and B and T in the afternoon of that day? (2) How many minutes does B drive to catch up with a, and how many kilometers are there from B? (3) What's the speed of a from 2pm to 5pm? (4) What's the speed of B?

(1) From tude: a starts at 1 pm, B starts at 2 pm, a starts for 1 hour, B starts to start; (2) 103-2 = 43 × 60 = 80 minutes, 50-1003 = 503 kilometers, B drives 80 minutes to catch up with a, at this time, the two people are still 503 kilometers away from B; (3) (50-20) / (5-2) = 10 km / h, a from the bottom

A. The distance between B and a is 160 km. A starts from a by bike with a speed of 20 km / h. B starts from B by motorcycle
The speed is three times as fast as a. two people set out at the same time, facing each other. How long does it take for them to meet each other? Please solve the equation with one variable

Let's meet in X hours
20x+20×3x=160
80x=160
x=2
A: after two hours

A and B set out from a and B at the same time. A rode a bicycle and B rode a motorcycle. They drove at a constant speed along the same route. It is known that their speed ratio is 2:5, and they met at a distance of 10.5 kilometers from the midpoint of the two places. How many kilometers are there between a and B? If B arrives at a in 21 minutes after meeting, what are the speed of bicycle and motorcycle?

(1) If the distance between a and B is divided into 7 equal parts, then a will walk 2 equal parts, and B will walk 5 equal parts; if they meet at 10.5km away from the midpoint of the two places, then B will walk 10.5 × 2 = 21 (km), and B will walk 3 equal parts more than a, so each equal part is 21 △ 3 = 7 (km), so the distance between a and B is 7 × 7 = 49 (km)