SOLUTION: Two fishing boats depart a harbor at the same time, one traveling east, the other south. The eastbound boat travels at a speed 7 mi/h faster than the southbound boat. After 6 h the

Algebra ->  Equations -> SOLUTION: Two fishing boats depart a harbor at the same time, one traveling east, the other south. The eastbound boat travels at a speed 7 mi/h faster than the southbound boat. After 6 h the      Log On


   

Question 1065079: Two fishing boats depart a harbor at the same time, one traveling east, the other south. The eastbound boat travels at a speed 7 mi/h faster than the southbound boat. After 6 h the boats are 78 mi apart. Find the speed of the southbound boat.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Their two separate distances are %28r%2B7%29%2A6 and %28r%29%286%29.

Departure point and the two travel location points form a right triangle.

%286%28r%2B7%29%29%5E2%2B%286r%29%5E2=78%5E2

36%28r%5E2%2B14r%2B49%29%2B36r%5E2=78%5E2
.
r%5E2%2B14r%2B49%2Br%5E2=169

2r%5E2%2B14r%2B49-169=0

2r%5E2%2B14r-120=0

r%5E2%2B7r-60=0
This is factorable.