Please give an explanation and answer or just answer

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Name each raycalculation tip: in ray "ab", a is the endpoint of the ray.

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28