Can you find the dog hidden in a group of pandas?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

John buys rice at Rs.60/kg from Britain and then sells them at Rs.5/kg in India. As a result of this, he becomes a millionaire. How come?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

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

which number am I?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?