Question

Fill In The Blanks

80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of following frequency table:

Life time (in hrs): 300 500 700 900 1000
Frequency : 10 12 23 25 10

One bulb is selected at random from the lot. The probability that its life is 1150 hours is __________.

Answer 1

Number of bulbs in the lot = 80

Number of bulbs having life time 1150 hours = 0

∴ P(Bulb selected at random has life time 1150 hours)

= $\frac{\mathrm{Number}\mathrm{of}\mathrm{bulbs}\mathrm{having}\mathrm{life}\mathrm{time}1150\mathrm{hours}}{\mathrm{Number}\mathrm{of}\mathrm{bulbs}\mathrm{in}\mathrm{the}\mathrm{lot}}$

= $\frac{0}{80}$

= 0

Thus, the probability that a bulb selected at random from the lot has life time 1150 hours is 0.

One bulb is selected at random from the lot. The probability that its life is 1150 hours is ____0____.