mchine X and Y

Machine X and Y work at their respective constatnt rates. HOW many more hour does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X ,working alone?

(1) Machine Y and X, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does
(2) machine Y, working alone, fills the production order of this size in twice the time that machine X, working alone

SOS!