If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

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

Which is the smallest number that you can write using all the vowels exactly once?

Can it be possible to build a house that has all its four walls facing towards the South?

I am 5 letters long.
My first two tell you who I am
My first 3 could be a medicine
My last three reversed could be a young boy.
My 4th, 3rd and 2nd in that order could be a fruit drink.
If you have me you may hang me round your neck
WHAT AM I ?

Count the number of triangles in the below picture?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?