A factory manufacturing car batteries made a survey in the field on the life of these batteries. The data obtained was as follows:
LifeTime (inmonths)Less than2424−3636−48morethan48TotalBatteriesNumber ofbatteries502405501601000
What is the probability that a battery chosen at random
(i) will not last more than 36 months?
(ii) will last for four years? [2 MARKS]
Solution: [1.5 Marks for each section]
Number of batteries that didn’t las for more than 36 months = 50 + 240 = 290
Probability that the battery will not last more than 36 months = 290/1000 = 0.29
Number of batteries that lasted 4 years = 160
Probability that a battery will last 4 years = 160/1000= 0.16