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sleepy_sentinel · 06-27-2007, 12:24 AM

Zorillo wrote:

'For example, what is the probability that a number amongst the first 1000 positive integers is divisible by 8? Don’t start counting the multiples of 8! The figure of 1000 is a red herring. Use a little common sense. The numbers will be 8,16,24,32…So, 1 in every 8 numbers is a multiple of 8, even if you consider the first million integers. So Probability is 1/8 (Question from Power-Prep.)'

Hi Zorrillo, I hate to nit-pick, but that approach only works because 1000 is divisible by 8.If the number mentioned was 999 or 1001, the probability would NOT have been 1/8.In my experience, its always better to do probability problems ab initio.
Great post otherwise.Do keep up the good work.

Cheers

06-27-2007, 12:24 AM	#51 (permalink)
sleepy_sentinel Trying to make mom and pop proud Join Date: Jun 2007 Posts: 21	Zorillo wrote: 'For example, what is the probability that a number amongst the first 1000 positive integers is divisible by 8? Don’t start counting the multiples of 8! The figure of 1000 is a red herring. Use a little common sense. The numbers will be 8,16,24,32…So, 1 in every 8 numbers is a multiple of 8, even if you consider the first million integers. So Probability is 1/8 (Question from Power-Prep.)' Hi Zorrillo, I hate to nit-pick, but that approach only works because 1000 is divisible by 8.If the number mentioned was 999 or 1001, the probability would NOT have been 1/8.In my experience, its always better to do probability problems ab initio. Great post otherwise.Do keep up the good work. Cheers