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 samples strength is less than 6250 kilograms per square centimeter? (b) what is the probability that a samples strength is between 5800 and 5900 kilograms per square centimeter? (c) what strength is exceeded by 95% of the samples?