As a result of testing 20,00 electric bulbs manufactured by a company it was found that the lifetime of the bulbs was normally distributed with a mean of life of 2040 hours with standard deviation of 60 hours on the basis of the information estimate the number of bulbs expected to burn for (1) more than 2150 hours (2) more than 2000 hours (3) less than 1960 hours (4) less than 2175 hours (5) between 1950 and 2200 hours