Answer:
48 passengers
x get off, and 3 gets on
so there are now 48 - x + 3 = 51 - x passengers on the train
half of the passenger gets off, and 7 gets on
so there are:
(51-x)/2 + 7 passenger on the train
given that ther are 22 passenger now
so,
22 = (51-x)/2 + 7
x = 21 <== answer
Step-by-step explanation: