You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

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

which number am I?

What has one eye, but can’t see?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

What 5-letter word typed in all capital letters can be read the same upside down?

An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

Spot 5 differences in two Christmas tree below:

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS