SOLUTION: I need help with ditance problems. A boat can travel 124 km. downstream in 4 hours. The same boat can travel 85 km. upstrream in 5 hours. Find the speed of the current and the spee

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Question 286105: I need help with ditance problems. A boat can travel 124 km. downstream in 4 hours. The same boat can travel 85 km. upstrream in 5 hours. Find the speed of the current and the speed of the boat in still water.
I have the distacne as 85 and 124, the time for the 85 as 5 and the time for 124 as 4 the rate just confuses me
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
124=(R+C)4 FOR THE DOWN STREAM TRIP [R=RATE OF THE BOAT, C=CURRENT SPEED]
124=4R+4C MULTIPLY BY 5
85=(R-C)5
85=5R-5C MULTIPLY BY 4 & ADD
620=20R+20C
340=20R-20C
-------------------
960=40R
R=960/40
R=24 KMH. FOR THE BOAT SPEED IN STILL WATER.
124=(24+C)4
124=96+4C
4C=124-96
4C=28
C=28/4
C=7 KMH IS THE SPEED OF THE CURRENT.
PROOF:
85=(24-7)5
85=17*5
85=85