DIFFERENCE b/w X & Y Mod(x-y) OR x-y

[Saurabh Malpani]

What does it Mean to ask DIFFERENCE b/w X & Y---> Mod(x-y) or Just X-Y ???

My question is also in refrence to the Challange Problem Published on 07/05/04. The questions Statement is

"Three years from today, the difference between the age of the boy and the combined ages of the girls will be"

So how what do you understand by this ---Boy - Girls or Girls -Boy

Don't you think the Question is Ambigious

Thanks
Saurabh Malpani

[StaceyKoprince]

Hi, Saurabh - can you please post the full text of the question and the answer choices? (You do not need to post the explanation - I just need to be able to read the full text to answer your question.)

Generally, a mention of the difference between two numbers could mean "either way" or it could mean "just one way" - it really depends upon the exact wording of the entire question.

[saurabh.malpani]

Stacey,

As requested, following is the complete problem:


07/05/04
Question
Roberto has three children: two girls and a boy. All were born on the same date in different years. The sum of the ages of the two girls today is smaller than the age of the boy today, but a year from now the sum of the ages of the girls will equal the age of the boy. Three years from today, the difference between the age of the boy and the combined ages of the girls will be

A) 1
B) 2
C) 3
D) -2
E) -1



Thanks
Saurabh Malpani

[Saurabh Malpani]

Stacey,

As requested, following is the complete problem:


07/05/04
Question
Roberto has three children: two girls and a boy. All were born on the same date in different years. The sum of the ages of the two girls today is smaller than the age of the boy today, but a year from now the sum of the ages of the girls will equal the age of the boy. Three years from today, the difference between the age of the boy and the combined ages of the girls will be

A) 1
B) 2
C) 3
D) -2
E) -1



Thanks
Saurabh Malpani

[StaceyKoprince]

Ah, I see. This is why you won't see challenge problems on the real test - these are harder than the real test. In the real world, I agree that it is ambiguous. On this question, the author expects you to translate the math literally - difference between boy and girls is boy - girl.

On the real test, they'd say something like "the positive difference" to make it clear. I think I mentioned this in another post, but challenge problems are not necessarily the best study tool - these are harder than what you'd see on the real test and, as such, not always terribly indicative of the way in which you need to solve problems on the real thing. They're fun if you want to challenge yourself, but your time is better spent on the real practice problems (either OG or the ones we write specifically to mimic the real test).

[Saurabh Malpani]

Hi Stacey,

Thank you very much for your explanation!! I appreciate you guidance. Yes I do agree that challeges are indeed very tough no doubt but they have benefited me quite a bit as they have changed the apporach I take for solving problem.

Yes I am quiting challenges for a week atleast before I take them up again!!!! but trust me I enjoi every bit of each of the Problem.

Thanks
Saurabh Malpani