Can anyone tell me a word in the English dictionary which has a silent 'z'?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Can you count the number of triangles in the given figure?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

Why is the Hole below a Lock?

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?