Suppose you have a credit card debt of $4,000. Last month the bank charged you $40 interest on the debt. The solution to the equation 40= 4000/12r represents the annual interest rate (r) on the credit card. Find the annual interest rate on the credit card.

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function. a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.