The first question is really easy. Just transform your words into numbers.
(3/5)(x+1) - (1/2)x = 3. Solve for x. About ten people have already done this, so I'm sure you get it. Your two integers are obviously "X" and "X+1".
The second one is a bit more fun. I would use this equation, r = (d/t). Rate equals distance over time. The two trains have two rates. The time is the same, and the distances are different.
Time1 = 325/(r+25) That's the passenger train.
Time2 = 200/r That's the freight train.
Now, Time1 and Time2 are equal, so:
200/r = 325/(r+25) !!!!!!!!!!!!!!!!!!!!! WOW!
Now solve for r. Here's a little hint at solving this, just in case:
I often just flip the fractions when the variables are stuck on the bottom. It's allowed.
r/200 = (r+25)/325
r = 40mph r+25 = 65mph
The end.
2006-12-30 11:15:16
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answer #1
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answered by Nick B 3
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(3/5)(n + 1) - (1/2)n = 3. Multiply both sides by 10 and get
6(n + 1) - 5n = 30; therefore (6-5)n + 6 = 30, or n = 24.
The integers are 24 and 25.
Proof - (3/5)25 - (1/2)24 = 15 - 12 = 3
speed * time = distance, so time = distance / speed .Let s be the speed of the freight train; then s + 25 is the speed of the passenger train, and
325 / (s+25) = 200 / s; thus 325 s = 200(s + 25) = 200 s + 5000.
Then 125 s = 5000, or s = 40.
Conclusions:
The speed of the freight train is 40 mph.
The speed of the passenger train is 65 mph.
The time in question is 5 hours.
Proof - 325 miles / 65 mph = 5 hours,
and also 200 miles / 40mph = 5 hours.
2006-12-30 18:40:12
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answer #2
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answered by wild_turkey_willie 5
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Let the integers be x and (x+1)
3/5 (x+1) - x/2 = 3
This is the equation you need
Multilpy out
3x/5 + 3/5 -x/2 = 3
Multiply both sides by 10 to get rid of the denominators
6x + 6 - 5x = 30
collect numbers on one side and xs on the other
x = 24. So next integer is 25
Check
15 - 12 = 3.......It works! so it's probably right
The train Qu.
For every hour that they travel, the passenger train goes 25 miles further than the freight tfain.
The journeys of 200 m and 325 miles take 5 hours .....
325 - 200 = 5 times 25
the slow train goes 200 miles in 5 hrs,
so it travels at 200/5 mph
=40 mph
The passenger train goes at 65mph
Check that 5 times 65 = 325...
Conclusion....It is quicker to travel by fast trains. That is the only thing I can conclude and I'm looking at this question through the eyes of a teacher. The bit about the conclusion is a very strange question.
You might like to ask your teacher why it was asked?
2006-12-30 18:22:53
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answer #3
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answered by rosie recipe 7
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1. Call the first integer x
3/5*(x+1) - 1/2*x = 3
0.1x + 0.6 = 3
0.1x = 2.4
x = 24
Integers: 24, 25
2. Let speed of passenger train = a and speed of freight train be b
We know that distance/speed = time, so 325/a = 200/b (equation 1)
In addition, a - b = 25
This implies a = b + 25 (equation 2)
Substitute equation 2 into equation 1:
325/(b+25) = 200/b
Cross-multiply: 200b + 5000 = 325b
125b = 5000
b = 40 mi/h
a = 40+25=65 mi/h
Moreover, time taken = 325/65 = 5 h
Conclusions: Speed of passenger train = 65 mi/h; speed of freight train = 40 mi/h; time taken for vehicles to cover the distances, namely 325 mi for passenger train and 200 mi for freight train, is 5 hours.
2006-12-30 18:54:15
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answer #4
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answered by The Alchemist 2
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rosie has the equation for the first problem and the equation for the second problem is 2x + 25 = 525
let the speed of the freight train = x
let the speed of the passenger train = x + 25
x + x = 2x and 325 + 200 = 525 or the total distance traveled by both trains
Isolate the variable and solve for x add 25 to get the speed of the passenger train.
2006-12-30 18:41:43
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answer #5
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answered by ikeman32 6
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edit: nevermind my answer was wrong
2006-12-30 19:11:28
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answer #6
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answered by Roman Soldier 5
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