Verbal Reasoning - Mental Ability Questions

Brother of mother — Uncle: Uncle's son — Cousin

Letters in the word           Letters in the alphabet

$$\begin{gathered} CHA \\ - - \end{gathered}$$                            $$\begin{gathered} CBA \\ - - \end{gathered}$$

$$\begin{gathered} RS \\ -- \end{gathered}$$                             $$\begin{gathered} RS \\ -- \end{gathered}$$       

first letter A with last letter Z
similarly 2nd last letter Y with 2nd letter B
Now 3rd letter C with 3rd last letter X
4th last letter W with 4th letter D
and so on....

Therefore the missing letter is X

If the first half of the English alphabet is reversed and the remaining part has been left undisturbed, then it becomes very easy to find out the required letters, if required letters come in the first half. According to the question, 10th to the left of 16th letter from the left = (16 - 10 =) 6th letter from the left in new series.

=>  6th letter from the left in new series = (13 + 1 - 6=) 8th letter from the left in the original series, i.e H.

A biped is an animal that uses two legs for walking and the quadrupeds are animals that use four legs for walking.

From the Given options, Cat only have 4 legs.

So Biped : Quadruped :: Ostrich : Cat.

The letter of the word are written in a reverse order and then each letter is moved one step backward to obtain the code.

P, Q, R are children of same parents. So. S who is R's mother and T, who is R's father will be mother and father of all three. 

However, it is not mentioned whether Q is male or female So, D cannot be definitely true. 

Clearly, From 1 to 100, there are ten numbers with 3 as the unit's digit - 3, 13, 23, 33, 43, 53, 63, 73, 83, 93 and ten numbers with 3 as the ten's digit - 30, 31, 32, 33, 34, 35, 36, 37, 38, 39.

So, required number = 10 + 10 = 20.