In a museum there is a round window decorated with circular rings of the same size as in the diagram. The radius of the window is 45cm. Calculate the area that is not covered by the decoration. (Use pi=3.142)

Little’s law firm has just one lawyer. customers arrive randomly at an average rate of 6 per 8 hour workday. service times have a mean of 50 minutes and a standard deviation of 20 minutes. how long does a customer spend at little’s law firm on average?

One card is dealt from a 52 card deck. find the probability that the dealt card is a 4 or a black 7

Find the area of the triangle shown 3 by 6