SOLUTION: THE SPEED OF A MOVING WALKAWAY IS TYPICALLY ABOUT 2.5 PER SECOND. WALKING ON SUCH A MOVING WALKAWAY, IT TAKES KAREN A TOTAL OF 40 SECONDS TO TRAVEL 50 FEET WITH THE MOVEMENT OF THE

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Question 648464: THE SPEED OF A MOVING WALKAWAY IS TYPICALLY ABOUT 2.5 PER SECOND. WALKING ON SUCH A MOVING WALKAWAY, IT TAKES KAREN A TOTAL OF 40 SECONDS TO TRAVEL 50 FEET WITH THE MOVEMENT OF THE WALKAWAY AND THEN BACK AGAIN AGAINST THE MOVEMENT OF THE WALKAWAY. WHAT IS KAREN'S NORMAL WALKING SPEED?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
THE SPEED OF A MOVING WALKAWAY IS TYPICALLY ABOUT 2.5 PER SECOND.
WALKING ON SUCH A MOVING WALKAWAY, IT TAKES KAREN A TOTAL OF 40 SECONDS TO
TRAVEL 50 FEET WITH THE MOVEMENT OF THE WALKAWAY AND THEN BACK AGAIN AGAINST
THE MOVEMENT OF THE WALKAWAY.
WHAT IS KAREN'S NORMAL WALKING SPEED?
:
Let w = normal walking speed in ft/sec
Then
(w+2.5) = effective speed with the walkway
and
(w-2.5) = effective speed against the walkway
:
Write a time equation: time = dist/speed
:
Time with + time against = 40 sec
50%2F%28%28w%2B2.5%29%29 + 50%2F%28%28w-2.5%29%29 = 40
:
Multiply by (w+2.5)(w-2.5); results:
50(w-2.5) + 50(w+2.5) = 40(w-2.5)(w+2.5)
:
50w - 125 + 50w + 125 = 40(w^2-6.25)
:
100w = 40(w^2-6.25)
divide both sides by 20
5w = 2(w^2-6.25)
5w = 2w^2 - 12.5
A quadratic equation
2w^2 - 5w - 12.5 = 0
Use the quadratic formula to find w; a=2; b=-5; c=-12.5
:
I got a positive solution ~ 4.045 ft/sec, normal walking speed, see what you get