0 as even number in PS and DS questions

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mmslf75
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Topic: 0 as even number in PS and DS questions
PostSun Sep 06, 2009 8:47 pm Reply with quote
Hi

When we have a question wherein there is a requirement to test for EVEN number..
Shld we consider " 0 " as even and test conditions.
i have done this many times especially in DS sums and have hit on the correct answer..

BUT....

As I came across a problem of OG 12 wherein it was asked to find out sum of all even numbers from 99 to 300. Here, the soln. states that 300 is 150th Even number.. But here we arent considering " 0 " as even...

What am I missing here ??
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mmslf75
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PostFri Nov 06, 2009 9:46 pm Reply with quote
Pls help guys !!
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palvarez
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PostFri Nov 06, 2009 10:21 pm Reply with quote
0 is neither positive nor negative

0 is an even integer.
2 is a positive even integer
-2 is a negative even integer

300 is an even integer, because it is divisible by 2.
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Testluv
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PostFri Nov 06, 2009 11:10 pm Reply with quote
mmslf75 wrote:
Hi

When we have a question wherein there is a requirement to test for EVEN number..
Shld we consider " 0 " as even and test conditions.
i have done this many times especially in DS sums and have hit on the correct answer..

BUT....

As I came across a problem of OG 12 wherein it was asked to find out sum of all even numbers from 99 to 300. Here, the soln. states that 300 is 150th Even number.. But here we arent considering " 0 " as even...

What am I missing here ??
Hi mmslf75,

all of palvaraz' comments are correct.

Counting from 1 to 300, 300 is the 300th number. Therefore, it is the 150th even number. In any evenly numbered set of consecutive numbers, half the numbers are even and half are odd.

300 is an even number. Counting from 1 to 300, there are 300 numbers in the set. 150 of them are even and 150 are odd.

If we had 301 numbers, going from 1 to 301, then 150 are even and 151 are odd. Therefore, in any oddly numbered set of consecutive numbers, you will either have one extra odd or else one extra even number (depending on where you started).

It is not that the OG was ignoring zero; if that were the case, then you could also say they were ignoring all the negative even integers as well!
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