SOLUTION: if A walked 1km/hr faster then A would have taken 10 min less to walk 2km/hr. find the speed of A

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Question 672211: if A walked 1km/hr faster then A would have taken 10 min less to walk 2km/hr. find the speed of A
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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if A walked 1km/hr faster then A would have taken 10 min less to walk 2km/hr. find the speed of A
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let s = the speed of A
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Change 10 min to 10/60 = 1/6 hr
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slow time - fast time = 10 min
2%2Fs - 2%2F%28%28s%2B1%29%29 = 1%2F6
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mult by 6s(s+1), cancel the denominators and you have:
6(s+1)*2 - 6s(2) = s(s+1)
12(s+1) - 12s = s^2 + s
12s + 12 - 12s = s^2 + s
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A quadratic equation
s^2 + s - 12 = 0
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Factors to
(s+4)(s-3) = 0
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the positive solution is what we want here
s = 3 km/h is his speed
:
:
Check this
2/3 - 2/4 =
8/12 - 6/12 = 2/12 = 1/6