What is common among 11, 69, and 88?

Can you find a five letter word that is left with only two letters if one is removed?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

What occurs twice in a week, once in a year but never in a day?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C