A. The distance between B and a is 450 km. A and B start from a and B at the same time and run in opposite directions. It is known that the speed of a is 120 km / h and that of B is 80 km / h. After t hours, the distance between two vehicles is 50 km, then the value of T is () A. 2 or 2.5B. 2 or 10C. 10 or 12.5d. 2 or 12.5

A. The distance between B and a is 450 km. A and B start from a and B at the same time and run in opposite directions. It is known that the speed of a is 120 km / h and that of B is 80 km / h. After t hours, the distance between two vehicles is 50 km, then the value of T is () A. 2 or 2.5B. 2 or 10C. 10 or 12.5d. 2 or 12.5

(1) When car a and car B do not meet, according to the meaning of the question, we get 120t + 80t = 450-50, and the solution is t = 2; (2) when the two cars meet and the distance between them is 50km, according to the meaning of the question, we get 120t + 80t = 450 + 50, and the solution is t = 2.5

AB is 450 km away from each other. Car a and car B start from ab at the same time and run in opposite directions. The speed of car a is 120 km / h and that of car B is 80 km / h. After t hours, the distance between the two cars is 50 km. What is the value of T?

(450-50)÷(120+80)
=400÷200
=2
or
(450+50)÷(120+80)
=500÷200
=2.5
So t = 2 or T = 2.5

The speed of vehicle a and vehicle B is 60km / h and 40km / h respectively in front of vehicle A. how long will it take for vehicle a to catch up with vehicle B

120 / (60-40) = 6 (hours)