What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

What does this Rebus Picture means ?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

John is the son of Jacob.
So,
Jacob is the_____of John's father?