If x and y are integers and x=50y + 29, which of the following must be odd? Choose one:
A) xy B) x + y C) 3X-1 D) 3x-1 E) X+2Y
x = 50y + 69, since y is integer, 50y will always be even hence 50y + 69 will be odd hence x = odd   you don't know whether Y is even or odd, so you need to try.   A: odd * even = even ; odd*odd= odd -&gt;not true   B: odd + odd = even ; odd+even = odd -&gt; not true   E: odd + 2*odd = odd ; odd + 2*even = odd -&gt; TRUE, stop here.   D: X+2YVX+2YN , C--X+2YVX+2YN   Answer X+2Y
<result>E</result>
If x and y are integers and x=50y + 29, which of the following must be odd?