Question

If $a$ is an odd integer and $b$ is an even integer, which of the following is an odd integer?

• A. $3b$
• B. $a+3$
• C. $2(a+b)$
• D. $a+2b$
• E. $2a+b$

Answer 1

The correct option is D $a+2b$

If $a$ is odd and $b$ is even, then

A. $3b=3\times even=even$

B. $a+3=odd+odd=even$

C.$2(a+b)=2\times (odd+even)=2\left(odd\right)=even$

D. $a+2b=odd+2\left(even\right)=odd+even=odd$

E. $2a+b=2\left(odd\right)+even=even+even=even$

Hence 'D' is correct choice