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Sequences

by ashish2104 » Mon Aug 16, 2010 1:09 am
209. After the first term, each term in a sequence is five times greater than half the preceding term. If x is the first term of the sequence, and x does not equal zero, what is the value of the fourth term minus the second term an integer?
(1) x is a multiple of 12.
(2) x is a multiple of 56.



I am not sure how the ans is B.Morever, I dont the answer is offical answer. I think answer should be E. Any comments.
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by sanju09 » Mon Aug 16, 2010 1:37 am
ashish2104 wrote:209. After the first term, each term in a sequence is five times greater than half the preceding term. If x is the first term of the sequence, and x does not equal zero, what is was the value of the fourth term minus the second term an integer?
(1) x is a multiple of 12.
(2) x is a multiple of 56.



I am not sure how the ans is B.Morever, I dont the answer is offical answer. I think answer should be E. Any comments.
When x is the first term, 5 x/2 is the second, 25 x/4 the third, and 125 x/8 the fourth one. Now, the value of the fourth term minus the second term

= 125 x/8 - 5 x/2

= 105 x/8

I think the correct wordings of the question are

Was the value of the fourth term minus the second term an integer?

or Is the value 105 x/8 an integer?

(1) A multiple of 12 is not necessarily a multiple of 8. Insufficient

(2) A multiple of 56 is always a multiple of 8. [spoiler]Sufficient


B[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



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by ashish2104 » Mon Aug 16, 2010 1:45 am
Yes Sanju, I agree with your ANs B for the new question where 105x/8 is an integer.
But for the given question, even after taking both options we have indefinite values as x would be a multiple of 168.
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by sanju09 » Tue Aug 17, 2010 4:54 am
ashish2104 wrote:Yes Sanju, I agree with your ANs B for the new question where 105x/8 is an integer.
But for the given question, even after taking both options we have indefinite values as x would be a multiple of 168.
I can't see in my post where I termed 105 x/8 as a given integer. This is in fact the core question to be answered, please read again

Is the value 105 x/8 an integer?

The answer solely depends on the value of x, that is, if x is a multiple of 8, then only the value 105 x/8 is an integer. Statement 1 doesn't provide the surety whereas Statement 2 does.


Can you please provide us with the right interpretation of this Grammar?
If x is the first term of the sequence, and x does not equal zero, what is the value of the fourth term minus the second term an integer?
The mind is everything. What you think you become. -Lord Buddha



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The Princeton Review - Manya Abroad
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by ashish2104 » Tue Aug 17, 2010 5:51 am
Ryt Sanju. I think i missed reading the last word.....A big mistake, which I hope not to repeat on test day.
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by gmatmachoman » Tue Aug 17, 2010 5:54 am
ashish2104 wrote:Ryt Sanju. I think i missed reading the last word.....A big mistake, which I hope not to repeat on test day.
Ashish, we never said u wrongly interpreted the question..we just said that the question is worded wrongly...
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