CBSE Class 10 Answered
x and y are positive integers.
thus, y = 2m for some positive integer m
(x+y) is odd number
so, x+y = 2n +1 for some n in N.
x+3y = x+y+2y
n and m are positive integers, hence n+m is also a positive integer say k
x+3y = 2k+1
hence, x+3y is odd number.