As part of the company program. ABC Company conducts test on battery life.The mean life is 20 hours.The useful life of batteries follow the normal distribution with a standard deviation of 1.12.

Questions.

A. About 70% of the batteries failed between what two values?
B. About what proportion of batteries produce failed above 19 hours?
C. If the company produces 30000 batteries a day, how many of this lot is expected to fail below 18 hours?