Well, as you know, there are 60 minutes in 1 hour. So you just have to compare. So;
60 minutes= 1 hour
180 minutes= y hours
I represented the unknown with y as you can see. Anyway, you have to cross multiply. So 1 multiplies 180 and 60 multiplies y. So that will be;
60y=180
Divide the both sides by 60. So;
60y/60=180/60
y=3 hours.
So the answer is 3 hours. Hope i helped. Have a nice day