Aplane flew a total of 2,220 miles. its average speed was 555 miles per hour. how many hours did the plane fly?

Ok. I will put my explanation in the answer box because apparently it's not good enough in the comments.

2220 divided by 555 is 4.
We do this equation because we need to find out how many 555 miles go into 2220 miles. The answer is 4, which we need to convert to hours, so it is 4 hours.
1 hour is 555 miles
2 hours are 1110 miles.
3 hours are 1665 miles.
4 hours are 2220 miles which is what we need.