What word begins and ends with an E, but has only one letter?

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?

John was piloting a plane behind a car but was never able to overtake it. Why?

Imagine you are in a room with no windows or doors. How will you get out?

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

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

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

* *
x *
=====
* * *

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

There is an ancient kingdom where every married woman keeps information regarding the fidelity of other men. However, what they don't know is the fidelity of their own husbands. Also, there is an ancient belief that they don't tell each other about the fidelity of their husbands.

On a certain day, the queen of the kingdom declares that she has identified at least one unfaithful man in the kingdom. She allows the wives to identify and gives them authority to kill their husbands if they are unfaithful at midnight.

How will the wives manage it?