In an A.P (p+1)th term is twice the (q+1)th terms. If its (3p+1)th term is λ times the (p+q+1)th term, then λ is equal to:
If (p+1)th term of an A.P is twice (q+1)th term, Prove that (3p+1)th term is twice the (p+q+1)th term.