SOLUTION: A motorboat can travel upstream on a river at 18 km/h and downstream at 30 km/h. How far upstream can the boat travel if it leaves at 8:00 AM and must return by noon?

Question 398821: A motorboat can travel upstream on a river at 18 km/h and downstream at 30 km/h. How far upstream can the boat travel if it leaves at 8:00 AM and must return by noon?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
The round trip from 8 - noon is 4 hours
Let = time for upstream trip
Then = time for downstream trip
Going upstream:

Going downstream:

Then,

So, going upstream:

He travels 45 mi upstream

RELATED QUESTIONS
A motorboat can travel upstream on a river at 12 mph and downstream at 20 mph. How far... (answered by ankor@dixie-net.com)

A power boat can travel upstream on a river at 24km/h and downstream at 30km/h. How far... (answered by drj,MathTherapy)

1. Bob left Boston at 9:00am and drove to New Hampshire at 60 km/h. Mike left Boston at (answered by Paul)

A small boat traveled upstream on a river at 10km/h and return downstream at 14km/h. if... (answered by ankor@dixie-net.com)

A boat can travel at a speed of 15 kph in still water. The boat travels 40 km downstream... (answered by mananth)

bob is traveling in a canoe that can go downstream at 6 km/h and upstream at 2 km/h. If... (answered by lwsshak3)

The river boat Delta Duchess paddled upstream at 12 km/h, stopped for 2 h of sightseeing, (answered by ankor@dixie-net.com)

please help me solve this problem in quadratic equation; 1.a motorboat takes 4 hours to... (answered by stanbon)

the river boat delta duchess paddled upstream at 12 km/h, stopped for 2 hours of sight... (answered by ankor@dixie-net.com)