If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

Four men were in a boat on the lake. The boat turns over, and all four men sink to the bottom of the lake, yet not a single man got wet! Why?

Can you find the thief by just looking at the picture below?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

Different lights make me strange by changing me into different sizes. What am I?

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

What Time Should the last watch show in the below figure?

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
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* * *