How many odd integers > x and < y.

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by beatthegmatinsept » Tue Sep 07, 2010 12:33 pm
Adi_Pat wrote:How many odd integers > x and < y.

1. 12 even integers > x and < y
2. 24 integers >x and <y

OA B

I dont see the logic behind the OA. Any ideas !!!
Nice question. What's the source?

B is enough. Here's why:

If we know there are 24 integers between x and y, we can consider 2 possible scenarios:

i) where x is an odd integer, and y is an even integer. (since x and y are not included in the 24 integer count).
Consider x = 1, y = 26. In this case you get 12 odd integers.

ii) where x is an even integer, and y is an odd integer. (since x and y are not included in the 24 integer count).
Consider x = 2, y = 27. In this case you get 12 odd integers.

Since, x and/or y are not included in the count of odd integers, you get the same answer in either scenario.
Hence, B is enough.
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by Adi_Pat » Tue Sep 07, 2010 3:17 pm
beatthegmatinsept wrote:
Adi_Pat wrote:How many odd integers > x and < y.

1. 12 even integers > x and < y
2. 24 integers >x and <y

OA B

I dont see the logic behind the OA. Any ideas !!!
Nice question. What's the source?

B is enough. Here's why:

If we know there are 24 integers between x and y, we can consider 2 possible scenarios:

i) where x is an odd integer, and y is an even integer. (since x and y are not included in the 24 integer count).
Consider x = 1, y = 26. In this case you get 12 odd integers.

ii) where x is an even integer, and y is an odd integer. (since x and y are not included in the 24 integer count).
Consider x = 2, y = 27. In this case you get 12 odd integers.

Since, x and/or y are not included in the count of odd integers, you get the same answer in either scenario.
Hence, B is enough.

This was the issue...you assume that they are consecutive integers. it doesnt say that it the question. Source is
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by beatthegmatinsept » Tue Sep 07, 2010 3:19 pm
Adi_Pat wrote: This was the issue...you assume that they are consecutive integers. it doesnt say that it the question. Source is
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It doesnt have to. Assume actual numbers instead of x and y. Say the question asked how many odd integers between 5 and 26. You would know that the result will be the # of consecutive odd integers in that range.
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by Adi_Pat » Tue Sep 07, 2010 3:22 pm
beatthegmatinsept wrote:
Adi_Pat wrote: This was the issue...you assume that they are consecutive integers. it doesnt say that it the question. Source is
GMAT PREP.
It doesnt have to. Assume actual numbers instead of x and y. Say the question asked how many odd integers between 5 and 26. You would know that the result will be the # of consecutive odd integers in that range.
What if I assume theres 24 odd integers between x and y...or 24 even integers..wouldnt that change the answer..??