Managing your time isn't always easy. Finding time for the gym sometimes is even harder.
Be it studying, family or work. Life has it's own ways of interfering with our pursuit of muscle.
When i find myself stripped of time for an expanded period my go to strategy is HIT (High Intensity Training).
When doing HIT you are doing a much smaller amount of volume per workout and muscle. When i'm training HIT i usually do just one or two sets per muscle group, two for the big muscles like the lats and one for the biceps for example.
But the set you are doing is super-intense extremly slow reps to absolute failure. I usually train with a 3-1-4-1 cadence which means for example on the leg press: 3 seconds pressing the weight, 1 second of squeezing, 4 seconds slow negative rep and 1 second break between reps. With that much intensity you will be sweating in no time.
A typical HIT workout for me looks like this:
1 sets leg press
1 sets incline dumbbell bench press
1 sets lat pulldown
1 set face pulls
1 set machine lateral raise
1 set biceps curls (any variation)
1 set triceps pushdown
All in a real slow cadence but not much rest between exercises and sets.
Should take you less than an hour and really helps breaking down those muscle fibers.