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?
Diameter of wheel of a cycle is 21 cm. The cyclist takes 45 minutes to reach a destination at a speed of 16.5 km/hr. How many revolutions will the wheel make during the journey?