Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

In an office's desk, you find a unique method that shows the current day of the month. Two numbered cubes are used to depict the current date.

Can you find out the numbers on both the cubes so that each date can be mentioned using them?

Please note that you have to use both the cubes to display any date. Thus the 1st day must be represented by 01 and so on.

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

What can you serve, but never eat?

Which is the rope you never skip with?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?