Fraction conversion

[SerkanC396]

Hello everyone,

I have a rather short and general question: If x/y = z/p is then always y/x = p/z ?

I would appreciate a reply

[tim]

As long as none of the variables are 0, that is true.

[RonPurewal]

more generally, you should be able to verify or disprove these things by yourself.

in this case, just come up with a few pairs of fractions that are equal. (e.g., 1/2 = 5/10, or 7/5 = 21/15, or whatever).
then, flip them upside down and see whether the equivalence still works.
you'll VERY quickly discover that it does—and, even more importantly, you'll develop an intuition as to why this is so (basically, you're 'reducing' things in the same way both times; the process of 'reducing' the fractions is unaffected by turning them upside down).

...and you should also discover tim's exception (if any of the numbers are zero). zero is an important enough number that you should be sure to test it.

[RonPurewal]

most importantly, this whole mentality—if you don't see how/whether something works right away, then INVESTIGATE IT WITH SPECIFIC INSTANCES—is pretty much the key to this entire exam, especially data sufficiency.

this is a mentality that you should ALWAYS have. the GMAT is not a test of knowing things—it's a test of figuring things out.