Question 81580
let t equal the time at 40 mph ... so 5-t is the time at 30 mph ... the total distance is the sum of the distances at the two rates


40*t+30*(5-t)=180 ... 40t+150-30t=180 ... 10t=30 ... t=3 ... 3 hrs at 40 mph and 2 hrs at 30 mph