SOLUTION: Travis paddles his kayak in the harbor at Morro Bay, California, where the incoming tide has caused a current in the water. From the point where he enters the water, he paddles 2 m

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Question 572820: Travis paddles his kayak in the harbor at Morro Bay, California, where the incoming tide has caused a current in the water. From the point where he enters the water, he paddles 2 miles against the current, then turns around and paddles 2 miles back to where he started. His average speed when paddling with the current is 3 miles per hour faster than his speed against the current. If the complete trip (out and back) takes him 1.4 hours, find his average speed when he paddles against the current.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
2/y + 2/(y-3)=1.4
2y-6+2y=1.4
4y-6=7/5(y(y-3)
5(4y-3)=7y^2-21y
20y-30=7y^2-21y
7y^2-41y+30=0
a= 7 , b= -41 , c= 30

b^2-4ac= 1681 + -840
b^2-4ac= 841 %09sqrt%28%09841%09%29=%0929%09
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=( 41 + 29 )/ 14
x1= 5.00
x2=( 41 -29 ) / 14
x2= 0.86

speed with current = 5 mph
speed against = 2 mph