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(1) z has exactly one prime factor.
z could be 2, 3, 5, 7, 4, 9, 25, 49, etc.
NOT SUFFICIENT

(2) 18 < z < 32, and z has exactly three factors.
Given such range, z must be only 25 (factors of z is 1, 5, 25)
SUFFICIENT

FINAL ANSWER IS (B)
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What is the value of the integer z ?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.

Answer - B

Given z is an integer

1) z has exactly one prime factor -> z can me multiple values - 2, 3, 8, 9 etc -> Not sufficient

2) z has exactly 3 factors means z is a perfect square in range 18<z<32 -> Only number is 25 hence z = 25 -> Sufficient
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We are to determine the value of z, which is an integer.

Statement 1: z has exactly one prime factor
Insufficient. This is because 4, 9, 25, etc all have exactly one prime factor and could be z.

Statement 2: 18<z<32, and z has exactly three factors.
Sufficient. We know that only the square of a prime number has exactly three factors. And the only perfect square that falls within the given range is 25, and that is the square of 5, which is a prime number. Hence z is 25.

The answer is B.

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#1
z has exactly one prime factor. ; z= 2,4,8,16 .. 5 insufficient
#2
18 < z < 32, and z has exactly three factors.
only perfect squares have three factors ; in this case 25 ; is z
IMO B sufficient

What is the value of the integer z ?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.
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1) z has exactly one prime factor
Let "a" be the prime factor

possible - values of \( z = {a, a^2, a^3, ...}\)
Insufficient

2) \(18 < z < 32\)
and \(z \)has exactly three factors

Possible values of \(z = 5^2\) with factors \({1, 5, 5^2}\)
Sufficient

Option B
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What is the value of the integer z?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.

(1) every prime number has exactly one prime factor.
in range of 18 - 32, there are many prime numbers, such as 19, 23, 29, 31
=> Not suff

(2) z has exactly three factors => z is the square of a prime number
\(3^2 = 9 \)
\(5^2 = 25 \)
\(7^2 =49\)
18< z <32 => z=25

=> Suff

=> Choice B
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From stmnt (1), Z has many values. Not Sufficient.
From stmnt (2), 25 has only 3 factor .( B)
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What is the value of the integer z ?

(Statement1): z has exactly one prime factor.
—> z could be 2,3,9,16,25....
Insufficient

(2) 18 < z < 32, and z has exactly three factors.
—> in order z to have exactly 3 factors, z must be square number.
From 18 to 32, only 25 is a square number—> z = 25
Sufficient

The answer is B

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