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Number Properties

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Number Properties

by KICKGMATASS123 » Sat May 30, 2009 11:42 am
If each term in the sum a1 + a2 + a3 + ... +an is either 7 or 77 and the sum is equal to 350, which of the following could equal to n?

38 39 40 41 42
Answer:40

Can someone suggest a way to solve this??
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by dmateer25 » Sat May 30, 2009 11:52 am
Let x= the number of terms that are 7
Let y= the number of terms that are 77

7x + 77y = 350

7(x+11y) = 7 * 50
x + 11y =50


Plug in numbers for x starting with 0 and see the possibilities

y = 0
x = 50

50 isn't a possibility so this is out

y=1
x=39

40 total terms. Bingo.
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Re: Number Properties

by exhilaration » Sat May 30, 2009 12:00 pm
KICKGMATASS123 wrote:If each term in the sum a1 + a2 + a3 + ... +an is either 7 or 77 and the sum is equal to 350, which of the following could equal to n?

38 39 40 41 42
Answer:40

Can someone suggest a way to solve this??
https://www.beatthegmat.com/sequence-que ... 37589.html
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