If a and b are integers, is b even?
(1) 3a + 4b is even.
(2) 3a + 5b is even
tuf ques
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I think answer is "C"
Explanation -
Considering the following facts-
Odd*Odd=Odd
Odd*Even=Even
Even*Even=Even
Odd+Odd=Even
Odd +Even=Odd
Even+Even=Even
Now as per
1) a=Even where as b=Odd or Even hence INSUFFICIENT
2) a= Odd or Even, b= Odd or Even hence INSUFFICIENT
combining both
a=Even, b=Even
What is OA?
Explanation -
Considering the following facts-
Odd*Odd=Odd
Odd*Even=Even
Even*Even=Even
Odd+Odd=Even
Odd +Even=Odd
Even+Even=Even
Now as per
1) a=Even where as b=Odd or Even hence INSUFFICIENT
2) a= Odd or Even, b= Odd or Even hence INSUFFICIENT
combining both
a=Even, b=Even
What is OA?
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I would say answer is C
If a and b are integers, is b even?
(1) 3a + 4b is even.
to make 3a + 4b you must add odd+odd or even+even
4b is always even
but what about b? it can be odd or even, from (1) we only know that a is even
INSUFF
(2) 3a + 5b is even
even+even = even
to make 5b you must have b even
a is also even
odd+odd = even
5b must be odd, so b is odd
and a is odd
INSUFF
(1) and (2)
a-even so b is even
C
OA?
If a and b are integers, is b even?
(1) 3a + 4b is even.
to make 3a + 4b you must add odd+odd or even+even
4b is always even
but what about b? it can be odd or even, from (1) we only know that a is even
INSUFF
(2) 3a + 5b is even
even+even = even
to make 5b you must have b even
a is also even
odd+odd = even
5b must be odd, so b is odd
and a is odd
INSUFF
(1) and (2)
a-even so b is even
C
OA?
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IMO C
1) not sufficient
a b 3a+4b
e o e
e e e
2) 3a+5b=3a+4b+b
same drill, not sufficient
Both combined, 3a+4b+b=even and 3a+4b is even, b has to be even.
1) not sufficient
a b 3a+4b
e o e
e e e
2) 3a+5b=3a+4b+b
same drill, not sufficient
Both combined, 3a+4b+b=even and 3a+4b is even, b has to be even.
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