Properties of numbers

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Properties of numbers

by Labenia » Mon Jun 01, 2009 6:11 am
How many multiples of 4 are there between 12 and 96, inclusive?

Solution:
since 12 is the 3rd multiple of 4 (12=3x4) and 96 is the 24th multiple of 4(96=24x4), the number of multiples of 4 between 12 and 96, inclusive, is the same of as the number of integers between 3 and 24, inclusive, namely 24 -3 + 1= 22

My question: why plus one in 24 -3 + 1= 22?????

Please help! :)
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by pathaniaus » Mon Jun 01, 2009 6:40 am
96 - 12 = 84 numbers (not inclusive)
u want the multiples of 4 so u divide 84 by 4. 84/4=21
21 + 1 (according to formula in number properties) = 22
22 should be the answer.
Is this correct? I hope it helped

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by Labenia » Mon Jun 01, 2009 6:49 am
pathaniaus wrote:96 - 12 = 84 numbers (not inclusive)
u want the multiples of 4 so u divide 84 by 4. 84/4=21
21 + 1 (according to formula in number properties) = 22
22 should be the answer.
Is this correct? I hope it helped
I think I'm missing something again...
pathaniaus wrote:(according to formula in number properties)
Would you please tell me what formula you mean?

Thanks a lot.

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by gmat_dest » Mon Jun 01, 2009 8:30 am
I guess he meant,

The number of integers between X and Y inclusive is Y - X + 1.

Plugin some numbers and you will be able to validate the rule.

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by Labenia » Mon Jun 01, 2009 9:01 am
Thank you both! :wink: