math
posted by bashi on .
jim began a 131 mile bicycle trip to build up stamina for a triathlete competetion.unfortunately his bicycle chain broke, so he finished the trip walking. the whole trip took 4 hours. if jim walks at a rate of 3 miles per hour and rides at 37 miles per hour, find the amount of time he spent of the bicycle.

t1 = walking time
t2 = biking time
t1 + t2 = 4.00 hours
37*t2 + 3*t1 = 131 miles
3*t1 + 3*t2 = 12
34*t2 = 119
t2 = 3.5 hours (The biking time they ask for)
t1 = 0.5 hours