To complete 30 AAKRUTI shirts

Time consumed by Cutters = (30 $\times$ 30) = 900 mins

Time consumed by tailors = (30 $\times$ 60) = 1800 mins

Time consumed by assistants = (30 $\times$ 30) = 900 mins

Time available for cutters = (1200 – 900) = 300 mins

Time available for tailors = (3000 – 1800) = 1200 mins

Time available for Assistant = (1200 – 900) = 300 mins

As they are not working in this available time it is the idle time.

Hence total man hours that are idle = (300 + 1200 + 300) = 1800 mins = 30 hours.