The sum of three numbers is 252. If the first number is thrice the second and third number is two-third of the first, then the second number is :

Answer: Option C

Let the number is a, b, c
a = 3b       $$\frac{a}{b}$$ = $$\frac{3}{1}$$
c = $$\frac{2}{3}$$a       $$\frac{c}{a}$$ = $$\frac{2}{3}$$

c	a	b
2	3
	3	1

c : a : b = 2 : 3 : 1
So, (2 + 3 + 1) = 252 units
6 units → 252
1 unit → 42
3 units → 42 × 3
So, second number is = 42