X/5+ax/7=x-303, which is simplified to (28-5a)x= 10605, so x= 10605/(28-5a), because X is a positive integer, so 28-5a must be1.
Put on your armor and walk for x minutes.
When the total distance is 1, the speed of A is 1/50, and the speed of B is 1/40. Now, if B takes a two-minute break, it is equivalent to walking for one minute 1/60, that is, the speed is 1/60, so it is X/50+X/.