Got stumped with this one

[Sandman]

ABCD is a rectangle with sides of length x centimeters and width y centimeters, and a diagonal of length z centimeters. What is the measure, in centimeters, of the perimeter of ABCD?

1. x-y=z
2. z=13

[rey.fernandez]

What's the source of this question? The problem describes a rectangle that cannot exist.

Consider the right triangle formed by two adjacent sides of the rectangle and the diagonal. Its side lengths are x, y, and z, such that z is the length of the hypotenuse.

Statement (1) says that x-y=z. This implies that x=y+z. But this is impossible for a triangle. The sum of any two sides of a triangle must be greater than the third side.

Is this a typo?

[Sandman]

Heye..thanks for the reply.

No its not a typo..ive written it exactly like i found on the book.

This is a data sufficiency question from Princeton Review - Cracking the GMAT 2008 book i have. Its from the Math Test in the Book ( Bin Four - Hard Questions) and the answer provided is option C. I couldnt make any sense out of either. Maybe its a misprint.

[Sandman]

Ive got another question from the same book. I couldnt figure this one out either....

Q. The members of the newest recruiting class of a certain military organization are taking their physical conditioning test, and those who score in the bottom 16 percent will have to retest. If the scores are normally distributed and have an arithmetic mean of 72, what is the score at or below which the recruits will have to retest?

1. There are 500 recruits in the class.
2. 10 recruits scored 82 or higher.

[target790]

I also believe 1st question is wrong.Consider the following in the given rectangle.

1>x-y=z
Squaring on both sides


=>x2 + y2 -2xy =z2
from pythagoras theorem(x2 + y2=z2)

=>z2 -2xy =z2
which leaves xy=0

So the given rectangle can't even exists.

[Sandman]

Ya. I think the first question is misprint. But what about the other one..how do u solve that one ?

[tripathimani]

There is a typo in your book.

(1) states that x-y=7 (NOT x-y=z)
(2) z=13

A triangle is possible with this data

[daisy]

There is a typo in your book.

(1) states that x-y=7 (NOT x-y=z)
(2) z=13

A triangle is possible with this data[/quote

If x-y = 7, then IMO (B) fits over here.

By Statement 1:
Does not lead us to figure out the possible values of all the elements: x, y and z. Hence, Insufficient.

By Statement 2:
x = 12 and y = 5 then z = 13, then perimeter = 34
or
try any other combination of x and y where x + y > z and x^2 + y^2 = z^2.
This only satisfy when x = 12 and y = 5

Hence, IMO (B)

[Brent@GMATPrepNow]

Ive got another question from the same book. I couldnt figure this one out either....

Q. The members of the newest recruiting class of a certain military organization are taking their physical conditioning test, and those who score in the bottom 16 percent will have to retest. If the scores are normally distributed and have an arithmetic mean of 72, what is the score at or below which the recruits will have to retest?

1. There are 500 recruits in the class.
2. 10 recruits scored 82 or higher.

Where did you get this question?
Normal distributions are beyond the scope of the GMAT. To solve this question, you would need either a calculator or a table of something called "z-scores."
My advice: If you come across any more questions involving normal distributions, ignore them.

[Ian Stewart]

Ive got another question from the same book. I couldnt figure this one out either....

Q. The members of the newest recruiting class of a certain military organization are taking their physical conditioning test, and those who score in the bottom 16 percent will have to retest. If the scores are normally distributed and have an arithmetic mean of 72, what is the score at or below which the recruits will have to retest?

1. There are 500 recruits in the class.
2. 10 recruits scored 82 or higher.

I described what is wrong both with this question and with its solution in another thread:

www.beatthegmat.com/standard-deviation- ... 03-15.html

You absolutely do not need to know anything about normal distributions for the test, and you should ignore this question entirely; the math in the question is actually wrong, and in any case is irrelevant to GMAT test takers.