SOLUTION: Hello, I need help with a question for homework for Algebra. "Melissa walks 3km to the house of a friend and returns home on a bike. She averages 4km per hour faster when cyclin

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Question 1036540: Hello, I need help with a question for homework for Algebra.
"Melissa walks 3km to the house of a friend and returns home on a bike. She averages 4km per hour faster when cycling than when walking, and the total time for both trips is two hours/ Find her walking speed, given that the formula for calculating time (in hours) is: t=d/s
where d=distance (in km)
and s=speed (in km/h)"
I know that the walking speed is 1km/h but I cannot understand how to show the working algebraically.
If you could help I would be very grateful.
Kind Regards
Benjamin Austin
Answer by ikleyn(52787) (Show Source):
You can put this solution on YOUR website!
.
Hello, I need help with a question for homework for Algebra.
"Melissa walks 3km to the house of a friend and returns home on a bike. She averages 4km per hour faster when cycling than when walking,
and the total time for both trips is two hours/ Find her walking speed, given that the formula for calculating time (in hours) is: t=d/s
where d=distance (in km)
and s=speed (in km/h)"
I know that the walking speed is 1km/h but I cannot understand how to show the working algebraically.
If you could help I would be very grateful.
Kind Regards
Benjamin Austin
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Let u be Melissa's walking speed, in . Then her biking speed is (u+4) . The equation is + = 2 To solve it, multiply both sides by x*(x+4) to rid of denominators. You will get a quadratic equation. Simplify and solve. 3(x+4) + 3x = 2x*(x+4), 6x + 4 = , = , = , Factor left side (x-2)*(x+1) = 0. One root is x = -1. Disregard it as negative. The other root is x = 2 {{km/h}}}. Check if it is correct. Answer. Melissa's walking speed is 2 . Her biking speed is 6 .