Question

80 bulbs are selected at random from a lot and their life time in hrs) is recorded in
the form of a frequency table given below:
Life time in hours 300,500,700,900,1100
Frequency 10,12,23,25, 10
One bulb is selected at random from the lot. The probability that its life is 1150
hours, is:
(a) 1780
(b) 7/16
(c) 0
(d) 1​

Answer 1

Answer:

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