the following tables gives the life time of 500 CFL lamps
Life time : 9,10,11,12,,13,14,more than 14
No of lamp: 26, 71,82,102,89,77,53
total : 500
a bulb is selected at random . the probabilty that the life time fo the selected bulb is atmost 11 months is given by

• Total No. of bulbs (possibility for selecting one bulb randomly) = 500C1 = 500
  Total No. of favorable event of getting life time at most 11 months are 26,71,82 sum up as 179.
  So Probability = Favorable event / total events
  = 179/500
• 9 years agoHelpfull: Yes(0) No(0)
• 179/500.........................
• 9 years agoHelpfull: Yes(0) No(0)