PLS HELP ME ASAP , i chose a few but im not sure if there wrong or right pls just help

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?

Is this a polynomial function? i need to know asap

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30