Mary's Election campaign

[tonebeeze]

I was able to correctly arrive at the answer intuitively, however I would like to get the algebra down pat. Can someone please walk me through the algebraic translation. Thanks!

Mary persuaded n friends to donate $500 each to her election campaign, and then each of these n friends persuaded n more people to donate $500 each to Mary's campaign. If no one donated more than once and if there were no other donation, what was the value of n?

1. The first n people donated 1/16 of the total amount donated

2. The total amount donated was $120,000

OA = D

[Anurag@Gurome]

I was able to correctly arrive at the answer intuitively, however I would like to get the algebra down pat. Can someone please walk me through the algebraic translation. Thanks!

Mary persuaded n friends to donate $500 each to her election campaign, and then each of these n friends persuaded n more people to donate $500 each to Mary's campaign. If no one donated more than once and if there were no other donation, what was the value of n?

1. The first n people donated 1/16 of the total amount donated

2. The total amount donated was $120,000

OA = D

Donation by n friends = 500n
Then each of these n friends persuaded n more people to donate $500 each to Mary's campaign implies Donation = 500n²
Total donation = 500n + 500n² = 500n(n + 1)
We have to find n.

(1)(1/16){500n(n + 1)} = 500n, which can be solved for n.
So, (1) is SUFFICIENT.

(2) 500n(n + 1) = 120000, which can again be solved for n.
So, (2) is SUFFICIENT.

The correct answer is D.