SOLUTION: Two ferryboats leave opposite sides of a lake at the same time. They pass eachother when they are 800 meters from the nearest shore. When it reaches the opposite side, each boat sp

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Two ferryboats leave opposite sides of a lake at the same time. They pass eachother when they are 800 meters from the nearest shore. When it reaches the opposite side, each boat sp      Log On


   

Question 31062: Two ferryboats leave opposite sides of a lake at the same time. They pass eachother when they are 800 meters from the nearest shore. When it reaches the opposite side, each boat spends 30 minutes at the dock and then starts back. This time the boats pass each other when they are 400 meters from the nearest shore. Assuming that each of the boats travels at the same speed in both directions, how wide is the lake between the two ferry docks?
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Let the speed be x
800(x-30)=400(x+30)
800x-24000=400x+12000
400x=36000
x=90

800(90-30)=400(90+30)
48000=48000

Hence, the speed of the boats are 90meters per minute and the lake is 4800 meters wide or 48km wide.
Paul.