Adam started to run at a rate of 6 mph from city A towards city B, which is 18 miles away. Ten minutes later, Benjamin started to run from city B towards city Aand simultaneously, Caroline started to bicycle at a rate of 11 mph from city A towards city B. If Caroline caught up to Benjamin 50 minutes after passing Adam, what was Benjamin's rate in mph?
+128475 Adam runs at 6mph = (6/60)*88 = 8.8 ft / s
Caroline bikes at (11/60)* 88 = 242/15 ft/s
When Caroline starts to ride, Adam will have biked (8.8)ft/s * 600s = 5280 ft
So....it will take Caroline (5280) / (242/15 - 8.8) = 720 sec to catch Adam = 12 min
50 + 12 = 62 min after this she passes Benjamin = time that Benjamin has ridden
So she has biked 62 * 60 ( 242/15) = 60016 ft = 341/30 mi
So....Benjamin has run 18 - 341/30 = 199/30 mi in 62 min
So.....his rate is (199/30)mi ( 60/62) ≈ 6.42 mi/hr
