Prove that twice of ten is the same as twice of eleven.

What kind of band never plays music?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

You can see it everyday, But cannot touch it at will. What is it?

Why do we preferably have round manhole covers and not square ones?

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

What question can you never answer yes to?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

15 caves are arranged in a circle at the temple of doom. One of these caves has the treasure of gems and wealth. Each day the treasure keepers can move the treasure to an adjacent cave or can keep it in the same cave. Every day two treasure seekers visit the place and have enough time to enter any two caves of their choice.

How do the treasure seekers ensure that they find the treasure in the minimum number of possible days?