At station A
There were 45 passengers on the bus when it left station A
At station B, some passengers boarded the bus but no passenger alighted from it.
Let , number of passengers boarded at B = x
at B no of passenger = 45 + x
At station C, half of the passengers in the bus alighted and 20 passengers boarded it.
at C = \( {45 + x \over 2} + 20\)
Finally at station D, another half of the passengers in the bus alighted and 30 passengers boarded it (45 + x)/2 + 20)/2 + 30
There were 80 passengers on the bus as it left station D for station E.
(45 + x)/2 + 20)/2 + 30 = 80
(45 + x)/2 + 20)/2 = 50
(x + 45)/2 + 20 = 100
(x + 45)/2 = 80
x + 45 = 160
x = 115
number of passengers boarded at B = x = 115
