odd integers
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Gurpinder
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Q: x < odd integers < yfinance wrote:How many odd integers are there greater than integer X and less than integer Y??
1) There are 12 even integers between X & Y
2) There are 24 integers between X and Y?
1) We can't say that there are 12 odd integers because (1) we don't know what the END digits of this set are (2) we don't know whether this is a consecutive set or even the increment
2) Again same as above.
Together:
x < 24 integers < y
from (1) we know that there are 12 even, that must mean that there are 12 odd integers.
hence (c)
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.
- Alfred A. Montapert, Philosopher.
Choice 1), if there are 12 even integers, starting on an odd integer vs. starting on an even integer (i.e. the first number in the sequence is 1 vs. 2) impacts how many odd integers you will count. insufficient.
Using choice 2), we know there are 24 integers between x & y. automatically half of those integers must be odd. Regardless if the first integer is odd or even, you will pass 12 odd and 12 even integers. Sufficient.
Answer is B
Using choice 2), we know there are 24 integers between x & y. automatically half of those integers must be odd. Regardless if the first integer is odd or even, you will pass 12 odd and 12 even integers. Sufficient.
Answer is B
Gurpinder wrote:Q: x < odd integers < yfinance wrote:How many odd integers are there greater than integer X and less than integer Y??
1) There are 12 even integers between X & Y
2) There are 24 integers between X and Y?
1) We can't say that there are 12 odd integers because (1) we don't know what the END digits of this set are (2) we don't know whether this is a consecutive set or even the increment
2) Again same as above.
Together:
x < 24 integers < y
from (1) we know that there are 12 even, that must mean that there are 12 odd integers.
hence (c)
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gmatboost
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To see why the answer is B, let's go through the same question with a slight change:
How many odd integers are there greater than integer X and less than integer Y?
1) There are 2 even integers between X & Y
2) There are 4 integers between X and Y?
Statement 1
Could be X = 3, Y = 7 (4 and 6 in between) -> only 5 is in between
Could be X = 2, Y = 8 (4 and 6 in between) -> 3, 5, 7 all in between
[spoiler]Insuff.
[/spoiler]
Statement 2
Could be X = 3, Y = 8 (4-7 in between) -> 5, 7 in between
Could be X = 2, Y = 7 (3-6 in between) -> 3, 5 in between
[spoiler]This doesn't prove sufficiency, but it shows that in each case there are 2. More broadly, it is correct to say that half of the 4 integers must be odd, so we know it is 2.[/spoiler]
How many odd integers are there greater than integer X and less than integer Y?
1) There are 2 even integers between X & Y
2) There are 4 integers between X and Y?
Statement 1
Could be X = 3, Y = 7 (4 and 6 in between) -> only 5 is in between
Could be X = 2, Y = 8 (4 and 6 in between) -> 3, 5, 7 all in between
[spoiler]Insuff.
[/spoiler]
Statement 2
Could be X = 3, Y = 8 (4-7 in between) -> 5, 7 in between
Could be X = 2, Y = 7 (3-6 in between) -> 3, 5 in between
[spoiler]This doesn't prove sufficiency, but it shows that in each case there are 2. More broadly, it is correct to say that half of the 4 integers must be odd, so we know it is 2.[/spoiler]
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GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.
Also, check out the most useful GMAT Math blog on the internet here.
