Sarah has $2 worth of dimes and quarters. She has a total of 17 dimes and quarters altogether. By following the steps below, determine the number of dimes, x, and the number of quarters, y, that Sarah has.

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.