aroussel wrote:

MathRevolution wrote:

If x and y are positive integers and \(y(2^x)=24\), x=?

1) x≥2

2) y is even

I had the answer E.

Statement 1: If x is 2, 2x2=4, therefore 4x6=24

but also, if x is 6, 2x6=12, therefore 12x2=24, so insufficient

Statement 2: As above, y can be even, but x still not be exclusively determined, hence insufficient.

Both together - same examples, x could be 2 or 6, with y being even (in those cases 4 and 12), therefore both are insufficient = E??

24 is comprised of 2 x 2 x 2 x 3 = 24. So, the max power of x is 3.

(1) if x is 2, then 2^x = 4, then y must be 6. If x=3, then 2^x = 8, then y must be 3

(2) y might be 24, if x=0

y might be 12, if x =1 => not sufficient

(1)+(2)

a) if x=3, then y=3 - from st.2, y is even, not odd

b) if x = 2, then y=6 - the only values of x and y, hence C

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