Fitness training: Carly is training for a triathlon. In her training routine each week, she runs 7 times as far as she swims, and she bikes 3 times as far as she runs. One week she trained a total of 232 miles. How far did she run that week.
Given 7 r/s 3 b/r then 21 b/s
232 = r + b + s
232 = 7s + 21 s +s s then equals 8 mi 7s = r = 56 mi (and bike = 3r=168mi)