If y rounded to the nearest thousandth is .00x, is x > 2?

How come z=6 r 8? also. 6 has unique 3 factors 6=2*3*1

Bunuel wrote:
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Solution: C

Start with the easier of the two statements. If we only have the stimulus and statement (2), we don’t know what z refers to, so statement (2) is NOT sufficient. If we have only the stimulus and statement (1), we don’t know the value of z. This is usually enough to render a statement insufficient, but if you’re nervous, try a few numbers. If z is 3, y = 1/125 = .008; that says that x = 8. If z is 4, y is 1/625 = .0016; that says that x = 2. The statements conflict, so (1) is NOT sufficient. Together, z must be 4 – any number that has exactly three unique factors is a prime number squared, and the only number less than 9 that is a prime number squared is 4. (C).


How come z=6 r 8? also. 6 has unique 3 factors 6=2*3*1



As per the question (2) z has exactly three unique factors and is a positive integer less than 9.
Hence Z=4 , factors are 1, 2, 4
a is factor b means , b completely divides a .

if you check for 6 . Its factors are 1, 2, 3, 6

Also other way to calculate factors ( a^b * c^d ) where a and c are prime , then the number of factors = (b+1) (d+1)

Regards,
Press Kudos if you like the post .

6 has four factors not three: 1, 2, 3, and 6.
8 has four factors not three: 1, 2, 4, and 8.

Remember a positive integer is a factor of itself.

Bunuel - Pardon me for this silly doubt.

Don't we need numbers after thousandth to do rounding.

I marked this as A as i thought we cannot round off y = 0.008 as it does not have anything after 8 to round off
and rest all values of y tell x < 2

Can you please clarify the rounding concept?

1) take z=1, y=.02, take z= 3 then y= .008 , hence A,D ruled out
2) z can be anything so B ruled out

combine 1,2 z has 3 unique factors i.e. z is a perfect square hence its is 4 which is less than 9 as given , the factors are 1,2,4
so the value of y when z=4 is .0016 and when rounded off gives value .002 which is x = 2 and clearly is x>2 we have definite NO it is not
hence C is answer.

Dear Bunuel

The question says ''if y is rounded'. In statement 1, if z= 2....then y =0.008. I do not see any rounding process. 'Y' naturally without rounding is 0.008. How do we assume that 0.008 is rounded?

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