Which number sentence below matches this word problem? jen and marcus got 15 miles up river before they ran out of gas. they floated 9 miles back down river before they reached the shore. how far did they get? a.15 - 6 = 9 b.9 + 15 = 24 c.15 - 9 = 6 d.135 9 = 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?