Malia runs 5 miles in 1 hour. How many miles does she run in half an hour? In 2 1/2 hours?

OK so you take the 5 miles in one hour and divide that by 2 to find the half hour

x=5/2 x = 2.5 miles

To find the 2 1/2 hours you take the hour distance (5) double it and add the half hour distance

x = (5 x 2) + 2.5 x = 10 + 2.5 x=12.5 miles