SOLUTION: 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 decr
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Question 146063This question is from textbook
: 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? This question is from textbook
You can put this solution on YOUR website! 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
You can put this solution on YOUR website! 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?
:
Do this in thousands of dollars to avoid all those zero's
:
Let x = no. of members currently in the club
:
Cost per member
:
Original cost = Cost with 5 more + 2 = + 2
Multiply equation x(x+5) to get rid of the denominators
200(x+5) = 200x + 2x(x+5)
:
200x + 1000 = 200x + 2x^2 + 10x
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Arrange on the left as a quadratic equation:
2x^2 + 10x + 200x - 200x - 1000 = 0
:
2x^2 + 10x - 1000 = 0
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Simplify
x^2 + 5x - 500 = 0
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Factor to:
(x+25)(x-20) = 0
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Positive solution:
x = 20 original members
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Check solution
Cost originally: 200/20 = 10k
Cost with 5 more: 200/25 = 8k