d = r * t
Let the rate on the side roads be s. Then the rate on the freeway is s - 10.
t = d / r, so
15 / (s - 10) = 65 / s
15s = 65s - 650
650 = 50s
s = 13 mph
Her rate on the freeway is 3 mph. She can drive the 15 miles on the freeway in five hours, same as 65 miles on side roads at 13 mph.
2007-01-02 16:32:18
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answer #1
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answered by ? 6
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Let her rate on the freeway be x m/hour
Thus her rate on the side roads= (x+10) m/hour
Ella drives 65 miles in side roads and 15 miles on the freeway at same time.
We know that, time=distance/rate
thus,time on side roads=65/(x+10) hour
time on the freeway=15/x hour
Therefore,
65/(x+10)=15/x
=>65x=15x+150
=>50x=150
=>x=3
Thus
her rate on the freeway is x=3 m/hour
Thus her rate on the side roads= (x+10) m/hour=3+10=
13 m/hour
2007-01-02 16:37:13
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answer #2
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answered by i m gr8 3
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Time is the same, so you have two equations:
D(sideroads) / R(sideroads) = t
D(freeway) / R(freeway) = t
Equate these and substitute what you know:
65 / R = 15 / (R - 10)
Now cross multiply and solve
65(R - 10) = 15R
65R - 650 = 15R
50R = 650
R = 13
So she travels at 13 mph on the side roads and 3 mph on the freeway. Both trips take 5 hours.
2007-01-02 16:34:40
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answer #3
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answered by Puzzling 7
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We'll say the rate on the side road is r, while her rate on the freeway is r-10.
Side road: d=rt and t=d/r, so t=65/r
Freeway: d=(r-10)t and t=d/(r-10), so t=15/(r-10)
Since this is in the same amount of time and they both equal t, you set them equal to each other.
65/r=15/(r-10)
Now you cross multiply and solve
65(r-10)=15r
65r-650=15r
50r=650
r=13 mi/h
Ella was going 13 mi/h on the side roads.
2007-01-02 16:42:32
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answer #4
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answered by Nick R 4
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Let
65 = miles driven on the side roads
15 = miles driven on the freeway
r = rate driven on the side roads
r - 10 = rate driven on the freeway
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Porportional problem
Multiply the means
Multiply the extremes
65/r = 15/r - 10
The means are 15r
The extremes are 65(r - 10)
15r = 65(r - 10
15r = 65r - 650
15r - 15r = 65r - 650 - 15r
0 = 50r - 650
0 + 650 = 50r - 650 + 650
650 = 50r
650 / 50 = 50r / 50
13 = r . . .rate on side road
The answer is r = 13
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2007-01-03 00:09:47
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answer #5
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answered by SAMUEL D 7
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Use the relationship time = distance/rate.
Let
s = speed on side streets
f = speed on freeway
Given
65/s = 15/f
s = f + 10
65f = 15s
13f = 3s = 3(f + 10) = 3f + 30
10f = 30
f = 3 miles/hour
s = 3 + 10 = 13 miles/hour
The speed on side streets is 13 miles/hour.
That's one bad traffic jam.
2007-01-02 16:36:37
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answer #6
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answered by Northstar 7
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If the scholars contemporary grade is a ninety% then we’re of direction assuming it’s out of a hundred% ninety/a hundred Now because of the fact the scholars grade more desirable 20% from the final grading era then you definately upload that to the previous a hundred% providing you with ninety/ one hundred twenty = .75 and because grades are in opportunities you multiply .75 via a hundred providing you with 75% because of the fact the scholars previous grade
2016-10-06 09:00:07
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answer #7
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answered by ? 4
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