WBCS Preliminary Examination 2021 — General Studies · Question 197 of 200

Answer: (C) (63, 8, 3)

In (8, 3, 2) each number is one less than the square of the next: $3^2-1=8$ and $2^2-1=3$. The same rule holds only for (63, 8, 3): $8^2-1=63$ and $3^2-1=8$. Check the rest: in (168, 15, 6), $15^2-1=224\neq168$; in (95, 24, 5), $24^2-1=575\neq95$ (though $5^2-1=24$ holds); in (15, 6, 5), $6^2-1=35\neq15$. Read such sets from right to left when the left-most number is the largest.