If eleven plus two equals one, what does nine plus five equal?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Can you figure out the logic I used to decide the order of the following words:
gun, shoe, spree, door, hive, kicks, heaven, gate, line, den

Find the value of "?" in the ball picture Riddle below:

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

Can you solve the photo plexer logic ?

Who are the happiest people in IPL match?

What begins with T, ends with T, and has T in it?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?