A can do a piece of work in 8 days and B can do it in 10 days seperately. How many days would it take for both A and B to finish the same work together?
Shrenik switched on a bulb at 2 : 39 : 40 hours and switched it off on the same day at 12 : 30 : 34 hours. For how long was the bulb in switched-on mode?