Calculating Period from Revolutions

[jenlikesmathsometimes]

I don't know why I can't figure this out. I remember doing these problems last year. Anyway:
When a car's engine makes less than about 185 revolutions per minute, it stalls. What is the period of the rotation of the engine when it is about to stall, in seconds?
Please help. Thanks.

 

[HallsofIvy]

You are aware, are you not, that there are 60 seconds in a minute? If the engine makes 185 revolutions in 60 seconds, how many does it make in 1 second? Once you have that, take the reciprocal to get number of seconds per revolution.