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?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

A sundial has the fewest moving parts of any timepiece. Which has the most?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

What am I?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

An office is divided into 8 cubicles. How many of the cubicles are painted if only 1/8 of the cubicles are painted?

I don't get anymore wetter, no matter how much rain falls on me.

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?