What is the common ratio in this geometric series?

What is the circumference of the pie

One file clerk can file 10 folders per minute. a second file clerk can file 11 folders per minute. how many minutes would the two clerks together take to file 672 folders?

The length of time it takes to find a parking space at 9 a.m. follows a normal distribution with a mean of 5 minutes and a standard deviation of 2 minutes. find the probability that it takes at least 8 minutes to find a parking space. (round your answer to four decimal places.)