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Bunuel
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Is the value of 3^a/3^b a prime number? (1) a + b = 8 (2) a – b = 2 01 Feb 2021, 13:44
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35% (medium)

Question Stats:

65% (01:13) correct 35% (01:37) wrong based on 62 sessions

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Is the value of 3^a/3^b a prime number?

(1) a + b = 8
(2) a – b = 2
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B
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Is the value of 3^a/3^b a prime number? (1) a + b = 8 (2) a – b = 2 01 Feb 2021, 19:16
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Bunuel
Is the value of 3^a/3^b a prime number?

(1) a + b = 8
(2) a – b = 2
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Is \(\frac{3^a}{3^b}\) a prime number?

\(\frac{3^a}{3^b}=3^{(a-b)}\)
It will be a prime, only when a-b=1. So, we look for whether a-b=1

(1) a + b = 8
a=5 and b=3....NO
a=4.5 and b=3.5...YES
Insuff

(2) a – b = 2
As a-b is not 1, the answer is NO
Suff

B
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