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by mandy12 » Mon Apr 14, 2008 8:58 pm
As per the basic time work rule ....

1/A+1/B = 5/6

1/B+1/C = 2/3

1/C +1/A = 1/2

Adding the above 3 equations we get

1/A+1/B+1/C = 1
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by AleksandrM » Sat Apr 19, 2008 5:50 am
Can you please show how you added the three above. I got to the first part without a problem with 5/6, 2/3, and 1/2, but could not move beyond that. I tried substitution, combining, but I ended up with A or B or C equaling a negative number.
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by Musiq » Sat Apr 19, 2008 6:38 am
AleksandrM wrote:Can you please show how you added the three above. I got to the first part without a problem with 5/6, 2/3, and 1/2, but could not move beyond that. I tried substitution, combining, but I ended up with A or B or C equaling a negative number.
Adding all three of those would give us:

2( 1/A + 1/B + 1/C).

And then divide both sides by 2, to get 1/A + 1/B +1/C

Hope this helps!
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by AleksandrM » Sat Apr 19, 2008 6:50 am
No, that does not help at all. In fact, it confused me more. Why are you multiplying the three fractions by 2. And as far as the "other side" goes, what is on the other side.

If it is: 1/A + 1/B + 1/C = 1/x

Then I do not see where the 2 came from, etc, etc, etc.
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by Musiq » Sat Apr 19, 2008 8:42 am
AleksandrM wrote:No, that does not help at all. In fact, it confused me more. Why are you multiplying the three fractions by 2. And as far as the "other side" goes, what is on the other side.

If it is: 1/A + 1/B + 1/C = 1/x

Then I do not see where the 2 came from, etc, etc, etc.
Ok, Trial 2:

These are the three equations:

......................................................................1/A+1/B = 5/6

......................................................................1/B+1/C = 2/3

......................................................................1/C +1/A = 1/2
________________________________________________________________
Add all three (+) {1/A + 1/B} + {1/B + 1/C} + {1/C + 1/A} = {5/6} +{2/3} +{1/2}

Combining like terms (which in this case are the 1/A, 1/B and 1/C)

2 (1/A) + 2(1/B) + 2(1/C) = 5/6 + 2/3 + 1/2
Or, 2 { 1/A +1/B + 1/C } = 12 /6
Or, 2{ 1/A +1/B + 1/C } = 2
Or, { 1/A +1/B + 1/C } = 2/2


Or, 1/A + 1/B +1/C = 1 day
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by AleksandrM » Sat Apr 19, 2008 10:35 am
Alright!!! :idea: Thanks so much musiq.
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by Musiq » Sat Apr 19, 2008 10:54 am
AleksandrM wrote:Alright!!! :idea: Thanks so much musiq.
No probs Aleksandr.

Thats what this forum is for. I help you, you help me.

Together we crack the GMAT :D
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