Can you tell a 3D object that has just two surfaces?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

Why Wine Glass Stem is so long?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

What does this mean?
N
A
E
L
C

If your uncle’s sister is not your aunt, what relation is she to you?

A B C D E F G H

These are the letters given to you. Now you have to find out the letter that comes two to the right of the letter which is immediately to the left of the letter that comes three to the right of the letter that comes midway between the letter two to the left of the letter C and the letter immediately to the right of the letter F.

I have branches, but no fruit, trunk or leaves. What am I?

What do you think with the below Picture ?