If a petrochemical plant manufactures a range of hazardous chemical products and must therefore follow strict guidelines concerning each of the chemicals may interact with one another on a daily basis. The plant processes five different chemicals every week. Three of these chemicals can be processed on any given day. Xenon may be processed any day except for every other Monday and every other Thursday.
Oxygen, however, can be processed only on Tuesdays and Wednesdays.
Liquid Hydrogen may be processed on Mondays, Wednesdays and Fridays.
Sulfur Dioxide can't be processed on Fridays.
Methane can't be processed on Wednesday.
Which day of the week is the only days that they can process Liquid Hydrogen so that they can process three chemicals?