HelloI just need help in part d

Q4: The compressive strength of samples of cement can be modeled by a normal distribution with a mean of 6000 kilograms per square centimeter and a standard deviation of 100 kilograms per square centimeter. (a) What is the probability that a sample's strength is less than 6320 Kg/cmZ? (b) What is the probability that a sample's strength is between 5750 and 5950 Kg/cm2? (c) What strength is exceeded by 95% of the samples? ((1) Determine strength that are symmetric about the mean that include 82%of all samples. Round your answers to six decimal places (16 points)