In a parking lot, some cars have 1 spare tire and others have no spare tires. All together, there are 43 tires and 9 cars. How many cars have a spare tire?

Question

In a parking lot, some cars have 1 spare tire and others have no spare tires. All together, there are 43 tires and 9 cars. How many cars have a spare tire?

Answer 1

9 cars

each car has 4 tires not including the spare

9*4=36 tires on 9 cars

there are 43 tires altogether

43-36=7 extra tires which must be the spares

7 cars have a spare