Okay so first, you have to find out how many miles the plane will fly altogether. So 8 trips and each trip is 810 miles : 8 x 810 = 6480
From there, you need to calculate how long flying 6480 miles will take the plane. If the plane flies 7 miles per minute, then it'll fly 6480 miles in about 925.7 minutes. But the question is asking for hours so then you divide 925.7 minutes by 60 (amount of minutes in an hour) and you get about 15.4 hours.
