Question 117200
a cruise boat travels 24 miles downstream in 3 hours and returns to its starting point upstream in 6 hours. find the speed of the stream.
-------------------
Downstream DATA:
distance = 24 miles ; time = 3 hrs ; rate = 24/3 = 8 mph
---------------
Upstream DATA:
distance = 24 miles ; time = 6 hrs ; rate = 4 mph
-------------
Let b = boat speed; let c = current speed.
----------------
EQUATIONS:
b+c = 8 mph
b-c = 4 mph
--------------
Add the two equations to solve for "b":
2b = 12
b = 6 mph ( boat speed in still water )
Substitute to solve for "c":
6 + c = 8
c = 2 mph (current speed)
============
Cheers,
Stan H.