A number of commuters were on a bus when it started its journey form the bus station. At the first bus stop, 1/7 of the commuters got off. At the second bus stop, 1/6 of the remaining commuters got off, .... At the sixth bus stop, half the number of commuters got off and the bus was left with only 4 commuters. How many commuters boarded the bus at the bus station?

1 answer

Let x = A of the commuters who boarded the bus at the bus station

x (1 - 1/7) (1 - 1/6) (1 - 1/5) (1 - 1/4) (1 - 1/3) (1 - 1/2) = 4
x (6/7) (5/6) (4/5) (3/4) (2/3) (1/2) = 4
x (1/7) = 4
x = 28