ASAP PLEZz

1. whats 2/3 plus 1/9 2. 5/7 plus 1/2 3.7/15 plus 2/15

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?

Need so much on this one how many yards?