Verbal Reasoning - Mental Ability Questions

Justification:      

We can find the code for 'home' from the second and third statements.

For finding the code for 'they', we need the code for 'go' which cannot be determined from the given data.
Clearly, statement A is not necessary.

When positions of first and the third alphabets of each of the words are interchanged, we have PAL  TUB  RAC  NOS  DIH

Clearly, PAL and TUB are the only meaningful words. These words are obtained from LAP and BUT respectively. 

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.

ten = 3(number of letters)
nine = 4(number of letters)
sixty = 5(number of letters)
ninety = 6(number of letters)
seventy = 7(number of letters)
sixtysix = 8(number of letters)
ninetysix=96(number of letters)

Then, likwise choose the number which has 9 letters in its Spelling.

Justification:   

In statements A and B, the common code word is 'na' and the common word is 'water'.

So, 'na' means 'water'.

In statements B and D, the common code word is 'jo' and the common word is 'life'.
So, 'jo' means 'life'.
Thus, in statements B, 'tod' represents 'is'.