What is Guna's age?
I. Guna, Vinay and Keshav are all of the same age.
II. Sum of ages of Vinay, Keshav and Arjun is 32; also, Arjun is as old as Vinay and Keshav together.

From Statement I. Guna, Vinay and Keshav are of same age. This alone cannot gives the answer. From Statement II. Sum of ages of Vinay, Keshav and Arjun is 32; also Arjun is as old as Vinay and Keshav together. Vinay + Keshav + Arjun = 32 ------ (1) Arjun = Keshav + Vinay -------- (2) Put equation (2) in (1) 2 Arjun = 32 Arjun = 16 yr Keshav + Vinay = 16 Guna is not mentioned in statement Il so it is not possible to get the answer from here. From I and II: Guna = Keshav = Vinay Keshav + Vijay = 16 Vinay 16/2 = 8 yr So, Guna = 8 yr So from I and Il we get the age of Guna. Hence, both statements together are Needed