INn FOUR hours Jennifer will travel 12 m/h x4 = 48 miles
it will take Thomas 48 miles / 4 m/hr = 12 hours to reach the bike in the meantime Jennifer has EIGHT hours of walking 3 m/hr x 8 = 24 miles form the bike Thomas now sets out at 10 m/h this is 10 - 3 = 7 m/h faster than Jennifer is walking he will close the 24 miles and catch Jennifer in 7 m/hr *x = 24 m
24/7hours
So Thomas walks for 12 hours then bikes for 24/7 hr = 15 3/7 hrs = ~ 15 hr 26 min