The employees of corporate "Clocks" have a fixed rule for working hours. All the employees start working at 16:00 and finish their work by 21:00. They take exactly one break during that time.
All the employees stop working when their work is half done and at the same time both the minute and the hour hand of the clock coincides. They all start back working again when the minute hand makes a 30° angle with the hour hand.
Assuming the rate of work of employees is constant throughout the work period, calculate the amount of time they spend on break.
Bonus Question: What would be the length of break if they worked from 15:00 to 21:00?