Yoy pick a random card from the following cards

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?

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

Multiply: 2.7 × (–3) × (–1.2). a. –9.72 b. –10.8 c. 10.8 d. 9.72