Answer:
$100
Step-by-step explanation:
Since they are renting 2 buses, they will need 2 bus drivers. They will tip each driver $20; this will be a total of 2(20) = $40.
This means they will have $240-$40 = $200 left for the buses.
They will be renting 2 buses; this gives them 200/2 = $100 for each bus.