10. Three friends are training for a marathon. Over the period of a week, they ran a total of 104 miles. Amy ran 28 miles, Joe ran twice as many as Amy, and Margo ran the remainder. The expression below describes the number of miles Margo ran. What is the number of miles that Margo ran? \[ (104-28-28 \cdot 2) \]

To solve how many miles Margo ran, we first calculate Joe's total miles. Since he ran twice as many as Amy, Joe ran \( 2 \times 28 = 56 \) miles. Then we can find the total miles Margo ran by substituting into the expression: \[ (104 - 28 - 56) \] Calculating that gives us: \[ 104 - 28 - 56 = 20 \] So, Margo ran 20 miles! Now, here’s a fun fact: running a marathon is not just about speed but also about strategy! Many runners use a method called "negative splits," where you run the second half of the race faster than the first half. It can be quite rewarding to finish strong, as Margo might do on race day! Additionally, keeping a reliable training log can help identify trends and make wiser training decisions. This is where runners jot down their daily mileage, feelings during runs, or even weather conditions. By reflecting on this data, Margo and her friends could optimize their future runs for success!