Bunuel wrote:

What is the value of integer z?

(1) z represents the remainder when positive integer x is divided by positive integer (x – 1)

(2) x is not a prime number

Kudos for a correct solution.

Target question: What is the value of integer z? Statement 1: z represents the remainder when positive integer x is divided by positive integer (x – 1) In almost all cases, we will get a remainder of 1 when we divide x by (x-1).

For example, 6 divided by 5 equals 1

with remainder 1 (in other words z = 1)9 divided by 8 equals 1

with remainder 1 (in other words z = 1)22 divided by 21 equals 1

with remainder 1 (in other words z = 1).

.

.

and so on.,

The only time we don't get a remainder of 1 is when x = 2

If x = 2, then x divided by (x-1) becomes 2 divided by 1, in which case the

remainder is 0 (in other words z = 0)Since we cannot answer the

target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: x is not a prime numberNo information about z

Statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined From statement 1, we learned that the remainder will always be 1 AS LONG as x does not equal 2

Statement 2 tells us that x does not equal 2

If x does not equal 2, then

dividing x by (x-1) will always leave remainder 1 In other words,

z must equal 1Since we can answer the

target question with certainty, the combined statements are SUFFICIENT

Answer: C

Cheers,

Brent

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