GCD of A and B

[BuZZ]

Find the GCD of A and B in terms of a and b, where a and b are positive numbers.

 

1) B is the product of b consecutive numbers beginning from a and A is b!.

2) A is the product of a and b. B is the quotient of a by b, also B is an integer.

[thebullfighter]

i think it should be B

 

nice Qs btw.

[Psyzygy]

I think it should be B as well.

 

St 1 is confusing but you cannot really find the GCD in terms of a and b :hmm: Anyone have a better idea?

[thebullfighter]

ws waiting for the OA, bt neverthless, this is my take(for stat1 ie.)

 

imo all that stat1 says is that B= a(a+1)(a+2).... And A= b(b-1)(b-2).....*1

Hence, => in B their is no term of b, & in A no term of a.

so, could this mean that "in terms of a & b" GCD of A & B is '1'

 

but, from stat2, we hd GCD= a/b. so, frm1, GCD=1 can't be possible.

Hence, frm2: we have GCD of A & B. but not from1. (as depending upon values of a & b, GCD of A & B could be 1 also, or any other number as well.)

 

Hence, B.

wat do u think psyzygy.

[BuZZ]

Given answer is D.

 

1) Try different numbers, you should find GCD as b!

a.........................1!

a(a+1)..................2!

a(a+1)(a+2)...........3!

etc.

 

2) GCD a/b

 

but, from stat2, we hd GCD= a/b. so, frm1, GCD=1 can't be possible.

Bull, the question is not from [tooltip=Official Guide]OG[/tooltip].

[thebullfighter]

Given answer is D.

 

1) Try different numbers, you should find GCD as b!

2) GCD a/b

 

Bull, the question is not from [tooltip=Official Guide]OG[/tooltip].

i don't understand. here r some quotes frm a thread, th link of which is also being provided. im totally confused now.

 

 

3. B (x=0)

Q3. This question makes no sense to me. If statement (1) uses the radical symbol, which by definition always means the positive square root, then x=3. The only integer that satisfies statement (2) is 0. So each statement alone answers the question, but they give different answers, which never happens on the GMAT. How can x be both 3 and 0?

I never knew that, I thought as long as each Statement gives us 'a' solution, it's ok. ie irrespective of if both the solutions match or not.

Coz. DS is a measure of telling if each statement is able to give us 'a' solution. I think it's more logical that way. Coz, this is wat i read as part if instructions in PP's DS section "EACH statement ALONE is sufficient to answer the Question asked;"

 

BUt anyways, as GMAT doen't see that logic...

let's just ignore Q3. n appologies for th same.

3)D ( yeah in GMAT there is always same answer from both the statements)

http://www.www.urch.com/forums/showthread.php?t=15400

[BuZZ]

Bull, I understood your concern. That's why I said above that this question in NOT from official guide of ETS.

 

Rest of the un-official guides could have such discrepancies.

 

Though, I never verified myself if all questions in [tooltip=Official Guide]OG[/tooltip]-DS really satisfy the rule as 800Bob mentioned above.

[thebullfighter]

o-k. fine dear. i also posted th above Q for bob only.

 

actually, IMO and also in th exam tht im to give (in india), different answers from diff. statements should be acceptable. but as i ws told on th other thread, so i changed my way of looking at DS while on TM and for GMAT prep. so, got confused & psychd out. thanx for clearing(i hav never used any gmat prep software or stuff, just PP. so didn't understand wat u said.)

 

now, here's wt i understand. pls correct me if im wrong.

 

In [tooltip=Official Guide]OG[/tooltip] Qs and Most importantly in GMAT we hav to go by wat bob told. ie Both statements will be giving Same answers. is it? pls clarify before my gmat.

thanx. & BOL.

 

regards.

Bull.

[thebullfighter]

This is important. So, pls can some1 who's Sure of wat rule ETS-GMAT follows help me, & othrs. spidy/erin/bob pls comment.

[spiderman]

yes it is true that all official questions end up with the same answer from both options. and no you dont have to worry even a bit in the main test trying to crunch the numbers and verify whether or not they are same. they will be the same. so, all you have to do is just see whether or not the options are sufficient to answer the question. the final number would take care of itself.

 

HTH.

[thebullfighter]

thts a relief. thanx 4ur prompt reply spidy. ws playin albartos on th othr site(1345 best). just read ur reply. thanx for th information (& th tip, bt tht brings another Q to my mind. i already end up in my quant with 10-15mins at spare, nw tht i don't even hav to calaulate values in DS, wat will i do man!!! any idea, as to if they'll allow me to play these Flash games in th meantime:D.)

[spiderman]

:D ... flirt with the test center incharge :p or psyche people next to you by telling them how easy the Quant section was ;)

[800Bob]

Absolutely. In real GMAT questions, statements (1) and (2) are always consistent. Think of each DS item as its own little universe. Within that universe, every time you see an x, for example, that x represents one and only one number. It can never happen on a real GMAT question that x represents one number in statement (1) and a different number in statement (2).

 

This leads to a strategy. If you think each statement alone answers the question, but they give different answers, then you know you have done something wrong and you should go back and look at the question and statements again. Note that this strategy works only on real GMAT questions. It is not a reliable strategy on Kaplan, Princeton Review, Barron's, Arco, or other non-official questions.