A Certain Brand of Flood Lamps Has a Lifetime That

Short Answer

A certain brand of flood lamps has a lifetime that is normally distributed with a mean of 3,750 hours and a standard deviation of 300 hours.
A)What proportion of these lamps will last for more than 4,000 hours?
B)What lifetime should the manufacturer advertise for these lamps in order that only 2% of the lamps will burn out before the advertised lifetime?
____________________ hours (Remove all commas from your answer before submitting).