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contribute to pay for the gift

by sanju09 » Wed Sep 15, 2010 1:11 am
A group of 10 people plan to contribute equally to pay for a friend's gift that costs G dollars. If n additional people want to contribute to pay for the gift, the required contribution per person will be reduced by how many dollars?
(A) G n/ (100 + 10 n)
(B) (10 + n)/ (G n)
(C) (10 G + G n)/n
(D) (G n + 10 G)/ (G n - 10)
(E) 10 G/ (n^2 + 10 n)



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by kmittal82 » Wed Sep 15, 2010 2:09 am
Original contrib per person = G/10

New contribution per person = G/(10+n)

Reduction in contribution per person = G/10 - G/(10+n)

Solve this to get Gn/10(10+n)

(A)
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by tpr-becky » Wed Sep 15, 2010 11:34 am
Because there are undefined variables in the answers this question can be quickly solved even if you aren't good at algebraic formulas - you can just pick numbers and work out the problem.

if we Say that the gift cost $100 so that if 10 people were contributing they would contribute $10 each. Now if we have 5 extra people contributing then the $100 gift will cost peole $6.66. Thus the price would have been reduced by $3.34.

Then you put the same numbers you used above into the answers to determine which answer will yield the same result. if you put these numbers into A you get (100)(5)/(100+10(5) which equals 500/150 which reduces to #3.34 and is thus your answer.
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