SOLUTION: Sailing with the current, a boat takes 3 hours to travel 48 miles. The return trip, against the current, takes 4 hours. Find the average speed of the boat for the entire trip and t

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Question 180172This question is from textbook Algebra 1
: Sailing with the current, a boat takes 3 hours to travel 48 miles. The return trip, against the current, takes 4 hours. Find the average speed of the boat for the entire trip and the speed of the current.
 This question is from textbook Algebra 1

Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!

Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
Average speed of the boat for the entire trip =total distance divided by total time
Average speed =(48+48)/7=96/7=13.71 mph


Let r1=rate of the boat in still water
Let r2=rate of the current
Now we know that:
r1+r2= =48/3=16 mph----------------eq1
r1-r2=48/4=12 mph------------------eq2

add eq1 and eq2:
2r1=28 divide each side by 2
r1=14 mph------------------------------rate of the boat in still water
substitute r1=14 mph into eq1:
14+r2=16 subtract 14 from each side
r2=2 mph----------------------------------rate of the current
Hope this helps---ptaylor