a class of 195 students went on a field trip. they took 7 vehicles, some cars and some buses. find the number of cars and the number of buses they took if each car holds 5 students and each bus hold 45 students.
+33616 Let c = number of cars and b = number of buses
c + b = 7 (1)
5c + 45b = 195 (2)
From (1): c = 7 - b (3)
Use (3) in (2)
5(7 - b) + 45b = 195
35 - 5b +45b = 195
35 + 40b = 195
40b = 160
b = 4
Put this back into (3)
c = 7 - 4
c = 3
So there were 3 cars and 4 buses
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