Amodified roulette wheel has 36 slots one is 0 and another is 00 the others are numbered 1-34 , you place an even number bet(0 & 00 do not count). what is your probability of winning? what are the odds? what is the payoff?

There are 34/2 = 17 even numbers

The chance of you winning is:
17/36*100 = 47.22%
which means that the odds are less than 50% (because of existance of 0 and 00 which dont count as even or odd) That simply means that on long run you cannot earn money by playing on even or odd numbers. That is the reason why roulette owners earn money.