Solution:

It is not possible to guess only three fruits correctly: the fourth fruit is then correct too! So nobody has guessed three fruits correctly and 123-43-39-31 = 10 people have guessed four fruits correctly.

Solution:

Silence

Solution:

An apple a day keeps the doctor away!

Solution:

A Hole

Solution:

F

Explanation: The letters are the first letter of each of the twelve months. The second month is February.

Solution:

fsh

no eye => no i
=> fish -i
=> fsh

lolz

Solution:

Draw an S in front of the IX and it spells SIX. No one said the line had to be straight.

Solution:

Just once, because after you subtract anything from it, it's not 100 anymore.

Solution:

Because, people turn them on.

Solution:

Neither, the accountant was his sister.