What is wrong in the below Picture?

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

A cat had three kittens: Snophy, Topsy and Jorden. What was the mother's name?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Find the smallest sentence with all the English alphabet.

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

Prove that the below maths equation is true.

8 + 8 = 91

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?