Sarah has 7 keys. Two of the keys unlock her desk drawer. If the first key she randomly chooses does not open the lock and she sets it aside, what is the probability that the second key she randomly chooses will unlock the drawer

Derricks dog sitting and darlene's dog sitting are competing for new business. the companies ran the ads shown. which dog sitting service is more economic to use if you need 5 hours of service? explain.

1. are the triangles similar and if so why? what is the value of x? show your work.

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?