Question 146063
The members of a flying club plan to share equally the cost of a $200,000 airplane. The members want to find five more people to join the club so that the cost per person will decrease by $2000. How many members are currently in the club?
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Let x = number of members currently in the club
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Current cost per member:
200000/x 
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If you added 5 new members, then the cost per member is:
200000/(x+5)
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your equation:
[200000/x] - [200000/(x+5)] = 2000
solving for x will yield your answer
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[200000/x] - [200000/(x+5)] = 2000
200000(x+5) - 200000(x) = 2000(x+5)(x)
200000x + 1000000 - 200000x = (2000x + 10000)(x)
1000000 = 2000x^2 + 10000x
0 = 2000x^2 + 10000x - 1000000
0 = x^2 + 5x - 500
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factoring:
(x+20)(x-25)
Since you can't have "negative" members, the solution must be: 20