Fitness

Summary: If you only have an hour per week to work out and want to make the most of it

• Avoid time consuming set ups and weight switching (e.g. opt for dumbbells and machines with weight stacks over barbells)
• Train multiple groups at once with compound exercises
• Train harder and go to failure more often
• Actually, train even harder and get closer to or past failure with drop sets

Nothing revolutionary here, but the advice is sound, and it's coming from a pretty reputable guy. Why is it getting so many downvotes? They're not saying this would be easy (and from experience, I can tell you it isn't), nor that it's a good way for beginners to get started.

Although...

you can get in and out of the gym in around 20 minutes. Do that 3 days a week

That might be a tad unrealistic. It takes five minutes to change and put away your bags. That leaves you with 10min to do your workout. Not worth it. Better to just do a full hour once a week and supplement with some bodyweight exercises at home.