Verbal Reasoning - Mental Ability Questions

Let first no. be "k" and multiple be "l"...start value of y with 3
then,
[(k x y) + {l x (l-1)}]
Thus, we get

15 x 3 + 3 x 2 = 51
51 x 4 + 4 x 3 = 216
216 x 5 + 5 x 4 = 1100
1100 x 6 + 6 x 5 = 6630
6630 x 7 + 7 x 6 = 46452

Therefore, the missing number is 6630.

Take a Look at the below sereies

2×1+12=3

3×2+22=10

10×3+32=39

39×4+42=172

172×5+52=885

Lethargic means "sluggish", kind of inactive

Vital means full of energy, lively

So, they are antonyms.

So, for the 2nd part of the analogy, you are looking for a antonym to trite

Trite means lacking originality or freshness. Overused. Kind of like a cliche

So, an antonym could be original, unique, innovative.

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. 

The correct order is :

Population    Unemployment    Poverty     Disease   Death

          2                   4                             1                    5           3