80 Bulbs Are Selected At Random From Lot

80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the … randomly from the lot has life less than…

Answers:

Number of bulbs having life less than 900 hours = 10 + 12 + 23 = 45 

P (a bulb has life less than 900 hours) = 45/80 = 9/16