CAN SOMEONE PLEASE HELP ME

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years

Піf x = y and y= z, which statement must be true? оа. -x = -2 b. x= z ос. —x = 2 od. 2= x