In the game of roulette, betting on either 0 or 00 (if you are playing American roulette) pays out at 35/1. If you are playing American roulette and do a "row bet", this means that you are betting on either 0 or 00. If the ball falls on either 0 or 00, you will receive a 17/1 payout.
If you bet on 0 or 00 on an American wheel, and your bet hits, you'll get a payout of 35 to 1. If you place a row bet (betting on both 0 and 00), and your bet hits, you'll get a payout of 17 to 1.