9batteries cost 18 dollars what's the rate and unit rate

1. the following set of data represents the number of waiting times in minutes from a random sample of 30 customers waiting for service at a department store. 4 5 7 10 11 11 12 12 13 15 15 17 17 17 17 17 18 20 20 21 22 22 23 24 25 27 27 31 31 32 a. determine the number of classes and class interval.

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Use the distance formula to find the distance between (-3,5) and (3,1)