1. Cost = room rental + transportation
Let units of cost be "dollars" and let "n" represent the number of people going on the field trip.
.. cost = 637 +18n
.. revenue = 105 +25n
2. You want to find "n" so that revenue matches cost.
.. revenue = cost
.. 105 +25n = 637 +18n
.. 7n = 532
.. n = 76
76 people need to make the trip to break even
