Help me with this please

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?

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?

Which must be true in order for the relationship △zyv ~ △xwv to be correct? zy ∥ wx ∠z ≅ ∠y and ∠w ≅ ∠x zv ≅ vy and wv ≅ vx ∠z ≅ ∠x and ∠w ≅ ∠y