If ab = c where a, b, and c are positive integers and a and b are prim

Question

If ab = c where a, b, and c are positive integers and a and b are prime numbers, what is the value of b?

(1) c is even.

(2) a is odd.

Archit3110 · Answer

ab=c
#1
c is even
a or b is 2
insuffieint
#2
a is odd
b can be even or odd insufficient
from 1 &2
a= odd and b = even
IMO C

rajatchopra1994 · Answer

Answer C Explanation: As given, A*B=C Only 2 is the even prime number, else all rest prime number is odd. We need the value of B. 1. Given C is even. So it will be only possible when either A or B is Even (as only one can be even prime number, As we want the result as odd number, i.e. C should be odd) So, Either A or B can be odd or even. so insufficient. 2. Now Given A is odd. So, resultant C (No details given) It can be odd or even A(odd) * B(odd or Even)= C (odd or Even) So insufficient 1&2, A(odd) * B(has to be even, as resultant is even)= C (Even) therefore, both statements 1 & 2 are required. So Answer is C Please provide kudos, if you find my answer explanation good enough

(really need of kudos)

Kinshook · Answer

Asked: If ab = c where a, b, and c are positive integers and a and b are prime numbers, what is the value of b?

(1) c is even.
a or b or both could be even prime number (2)
NOT SUFFICIENT

(2) a is odd.
b could be any prime number
NOT SUFFICIENT

(1) + (2)
(1) c is even.
(2) a is odd.
If c is even, and a is odd, b must be even prime number = 2
SUFFICIENT

IMO C

sanatg27 · Answer

2 scenarios

2x11 = 22
2x3 =6 
Hence C.

KTBFFH

nipunjain1904 · Answer

If ab = c where a, b, and c are positive integers and a and b are prime numbers, what is the value of b?

(1) c is even.

(2) a is odd.

Answer is C

Enrique92 · Answer

You need both to get a unique answers. Thus C

SaikatRoy · Answer

It's given ab = c where a, b, and c are positive integers and a and b are prime numbers.
And we need value of b.

Statement-1 states that c is even.
Now as ab=c, a or b or both could be even prime number ie 2.
Hence not sufficient.
Cancel AD.

Statement-2 states that a is odd.
Also ab=c, with b as could be any prime number
Hence not sufficient.
Cancel B

Taking statement (1) and (2) together we get c is even and a is odd.
Hence for ab=c, only way c is even is when b must be even prime number or 2
Or, Sufficient to give value of b.

Hence, Right Answer Is Option C

If ab = c where a, b, and c are positive integers and a and b are prim

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GMAT Data Sufficiency (DS) Questions

If ab = c where a, b, and c are positive integers and a and b are prim

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