Full parking lot

Question

all 20 spaces in my favorite parking lot are filled . some spaces are occupied by motorcycles and others occupied by cars. some people count to 10 when they get angry but that wasn't nearly far enough. I counted to 66 wheels to be exact. how many cars and how many motorcycles have invaded my territory?

Answer 1

m is number of motorcycles

c is number of cars

 

m + c = 20     or

m = 20 - c

 

2m is the number of wheels on motorcycles

4c is the number of wheels on cars

 

2m + 4c = 66         substituting for m

2(20 - c) + 4c = 66

40 - 2c + 4c = 66

40 + 2c = 66

2c = 26

c = 13

 

There are 13 cars and 7 motorcycles

 

Check:

 

4(13) + 2(7)

52 + 14

66