2.5*3 = 7.5 She run's 2 1/2 miles, which is equivalent to 2.5 miles, and 3 days per week, so you multiply 2.5 by 3
6.5 *2 = 13 She run's 6.5 miles per day for 2 days, again, because 6 1/2 is equivalent to 6.5 miles. Since she ran for 2 days so you multiply 6.5 by 2
13+7.5 = 20.5 miles
as for the answer, you just add the two numbers you got from Julie running