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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 .