SOLUTION: How in the world do you set this guy up?
A boat travels 25 miles per hour in still water. It takes 3 and 1/3 hours in total for the boat to travel 40 miles up a river and then r
Algebra.Com
Question 823236: How in the world do you set this guy up?
A boat travels 25 miles per hour in still water. It takes 3 and 1/3 hours in total for the boat to travel 40 miles up a river and then return by the same route. What is the speed of the current in the river?
Think you guys could help me set it up?
Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
---
s = d / t
t = d / s
T = 40/(25 - w) + 40/(25 + w)
T = 40(25 + w)/(25 - w)(25 + w) + 40(25 - w)/(25 - w)(25 + w)
T(25 - w)(25 + w) = 40(25 + w) + 40(25 - w)
T(625 - ww) = 1000 + 40w + 1000 - 40w
T(625 - ww) = 2000
625 - ww = 2000/T
T = 3+1/3 = 10/3
625 - ww = 2000/(10/3)
-ww + 625 = 600
-ww + 25 = 0
---
the above quadratic equation is in standard form, with a=-1, b=0, and c=25
---
to solve the quadratic equation, by using the quadratic formula, copy and paste this:
-1 0 25
into this solver: https://sooeet.com/math/quadratic-equation-solver.php
---
this quadratic has two real roots (the x-intercepts), which are:
w = -5
w = 5
---
negative speed doesn't make sense for this problem, so use the positive root
---
answer:
the speed of the current in the river is 5 mph
---
Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
---
Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
---
Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php
RELATED QUESTIONS
A boat travels 24 miles upstream in 3 hours. It then takes 3 hours to go 36 miles... (answered by richwmiller)
I am struggling in the set up of this problem. Can you please help me?
The current in... (answered by josmiceli)
The question is the rate that a boat travels in still water is r and the current speed is (answered by ankor@dixie-net.com)
The Hudson River flows at a rate of 3 miles per hour. A patrol boat travels 60 miles... (answered by Paul)
a boat travels 2 miles upstream and 2 miles downstream in 5 hours. in still water, the... (answered by mananth)
A boat travels at a constant rate of 8 miles per hour in still water. It travels upstream (answered by scott8148)
A boat travels at a constant rate of 8 miles per hour in still water. It travels upstream (answered by scott8148)
The speed of a boat in still water is 5 miles per hour. If the boat travels 3 miles... (answered by mananth)
It takes a boat 2 hours to travel 28 miles downstream and 4 hours to travel 24 miles... (answered by josmiceli,MathTherapy,greenestamps)