SOLUTION: Math Question--- A certain number of persons promised to subscribe equally to a girft of $600, five of them failed to keep their promise, and each of the other increased his sub

Question 758953: Math Question---
A certain number of persons promised to subscribe equally to a girft of $600, five of them failed to keep their promise, and each of the other increased his subscription by $10. The exact amount required was obtained. How many persons suscribed.
I have no idea how to do this question so PLEASE help!
Thank you for your time and help! :D
Found 3 solutions by stanbon, htmentor, MathTherapy:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
A certain number of persons promised to subscribe equally to a girft of $600, five of them failed to keep their promise, and each of the other increased his subscription by $10. The exact amount required was obtained. How many persons suscribed.
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Let the original # of people be "x.
Average contribution would be 600/x dollars.
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New # of people is (x-5).
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Contribution from x-5 people = $10
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Equation:
(x-5)(x/600 + 10) = 600
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(x-5)(x+6000)/600 = 600
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(x-5)(x+6000) = 360000
--------------------------
x^2 + 6000x-5x-30000 = 360000
x^2 + 5995x = 390000
x^2 + 5995x - 390000 = 0
-------------------
x = 64.36...
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Note: That doesn't look right.
The answer should be a whole number.
================
Cheers,
Stan H.
================
Answer by htmentor(1343)   (Show Source): You can put this solution on YOUR website!
Let n = the number of people who had promised to contribute
Let c = the pledged contribution amount
Since the required amount was $600, we have
n*c = 600
The new number of contributors = n - 5, and their contribution amount = c + 10
The amount raised is still the same, so we can write
(n-5)(c+10) = 600
Solve for c in the 1st equation, substitute in the 2nd:
(n-5)(600/n+10) = 600
Multiply and collect terms:
600 + 10n - 3000/n - 50 = 600
10n - 3000/n - 50 = 0
Multiply through by n, divide by 10:
n^2 - 5n - 300 = 0
Factor:
(n+15)(n-20) = 0
This gives n=20 (positive solution)
So the actual number of subscribers is 20-5 = 15
Their contribution was $40
Check:
15*40 = (15+5)(40-10) = 20*30 = 600
Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

Math Question---
A certain number of persons promised to subscribe equally to a girft of $600, five of them failed to keep their promise, and each of the other increased his subscription by $10. The exact amount required was obtained. How many persons suscribed.
I have no idea how to do this question so PLEASE help!
Thank you for your time and help! :D

Original number of subscribers =

You can do the check!!

Send comments and �thank-yous� to �D� at MathMadEzy@aol.com
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