Working together, Catherine and Giuliana can plant new trees on the recently deforest land in seven days. Working alone, it would take Giuliana three days longer than it would take Catherine to plant the trees. How long would it take Catherine working alone, to plant the trees?

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?

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter?

Solve the system by substitution. if the system is inconsistent or has dependent equations, say so. 5x-6y=-27 -5x+y=0