Solution:

Mahrez Pick 4 marbles.

Explanation:
How many marbles Vardy picks, Mahrez needs to make sure that only 1 marble is left after his move, So Vardy needs to pick the last marble.

Example:
If Vardy picks 1, Mahrez picks 5
If Vardy picks 2, Mahrez picks 4
....
...
If Vardy picks 5, Mahrez picks 1

Solution:

XI - I = X

Explanation:
Remove I (Roman equivalent of number 1) from the left side, you will the get the number on the right.
29 - 1 = 30
XXIX - I = XXX (Roman equivalent of number 30)

14 - 1 = 15
XIV - I = XV (Roman equivalent of number 15)

9 - 1 =10
IX - I = X (Roman equivalent of number 10)

Similarly,
11 - 1 = 10
XI - I = X (Roman equivalent of number 10)

Solution:

Step5 is Wrong.

Explanation:
We divided the two sides by (A-B).Since A = B which indicates that (A - B) = 0 and we cannot divide by zero.

Solution:

31

Explanation:
Ramanujan lighting the candles in binary.
11110 =30
11111 =31

Solution:

The alphabets

Explanation:
I have one eye but still, I am blind (Alphabet I)
I have a sea but there is no water. (Alphabet C)
I have a bee but there is no honey. (Alphabet B)
I have a tea but there is no coffee (Alphabet T)
Moreover, I have why but sadly there is no answer. (Alphabet Y)

Solution:

3

Explanation:
Digits are represented in binary form where a ball is 1 and a ring is 0.
001 = 1
010 = 2
100 = 4
011 = 3

Solution:

Felix

Explanation:
Iron = Fe (chemical symbol)
59 = LIX (Roman numerals)

Solution:

It can be done as shown below in the picture.

Solution:

Adam betrayed Eve.

Explanation:
Eve may not jump because of the survival instinct or can be related to some emotions and can, therefore, be given a benefit of the doubt, whereas Adam having the parachute seem a calculated plan implies that he definitely betrayed Eve.

Solution:

LOTTO

Explanation:
Just flip the two rows 1 and 2 vertically, you will find the word "Lotto".