An air-conditioning fan makes 125 revolutions per second. How many revolutions will it make if it runs for 30 minutes?
we know that
1 min=60 sec
we have
125 rev/sec
so
1 sec=1/60 min
substitute
125 rev/sec=125/ (1/60)=7,500 rev/min
Multiply by 30 min
7,500*30=225,000 rev
therefore
