About Math!(a simple question)

cheeyoung

PS: Both a and b are positive number. a/b and a-b are all even number. Which of the below is odd number?
answer is : a+2/2

Why?

zyh79

a-b,even==>b,even
because b,even and a/b,even
a=4 is multiplier of 4.
so a/2 even,1+a/2 odd