Q10 of 24 Page 97

The following table gives the lifetime of 500 CFL lamps.


A bulb is selected at random. Find the probability that the life time of the selected bulb is


(i) less than 12 months (ii) more than 14 months


(iii) at most 12 months (iv) at least 13 months

(i) less than 12 months includes the life of 9,10,11 months


⇒ (∵ the life of 26, 71, 82 bulbs are 9, 10, 11 among a total of 500 bulbs)


⇒


(ii) more than 14 months


⇒ (∵ the life of 53 bulbs is more than 14 months as per the data given)


(iii) At most 12 months


⇒ (∵ the life of 26, 71, 82, 102 bulbs are 9, 10, 11, 12 among a total of 500 bulbs)


⇒


(iv) At least 13 months


⇒ (∵ the life of 89, 77, 83 bulbs are 13, 14 and more than 14 months respectively among a total of 500 bulbs)


⇒


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