Which Burger Is Different in below image?

Before Mount Everest was discovered, what was the highest mountain in the world?

I know a nine-letter word having only one vowel.
Do you ?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

John was going on a jungle trip. He asked his wife to pack something to eat, something to drink and something to burn if he feels cold in the jungle. When John opens the backpack he found just one thing in the bag. What was it?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

By what process could you make a 'Tea-Table' into food?

There are forty elephants and they have forty-fore heads. How can this be possible?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?