Question
James drove the 24 miles to two and back in hour. On the return trip, he was able to average 20 miles per hour faster than he averaged on the trip to town. what was his average speed on the trip to town?
Answers
bobpursley
v= speed to town
time going=24/v
time coming=24/(v+20)
time going+timecoming=1hr
1=24/v + 24/(v+20)
v(v+20)=24(v+20)+24v
v^2+20v-48v-480=0
v^2-28v-480=0
v=(28+-sqrt(28^2+1920))/2
v=40
time going=24/v
time coming=24/(v+20)
time going+timecoming=1hr
1=24/v + 24/(v+20)
v(v+20)=24(v+20)+24v
v^2+20v-48v-480=0
v^2-28v-480=0
v=(28+-sqrt(28^2+1920))/2
v=40