The length of time a person takes to decide which shoes to purchase is normally distributed with a mean of 8.21 minutes and a standard deviation of 1.90. find the probability that a randomly selected individual will take less than 6 minutes to select a shoe purchase. is this outcome unusual?

Asequence is defined recursively by the formula  f(n  +  1)  =  f(n)  +  3 . the first term of the sequence is  –4. what is the next term in the sequence? –7–117

What is the domain and range of each function 1. x (3, 5, 7, 8, 11) y ( 6, 7, 7, 9, 14) 2. x (-3, -1, 2, 5, 7) y (9, 5, 4, -5, -7)

The rate of decay of a radioactive substance depends upon the amount present initially. the mass y (mg) of the radioactive substance cobalt-60 present in a sample at time t (years) is represented by the exponential equation y=50e −0.1315 t . answer the following questions in complete sentences. 1. how does the exponential equation above compare to the equation for simple interest that is compounded continuously? explain the similarities. 2. what is the initial amount of cobalt-60 in the sample? 2. how much cobalt-60 is left after 8.4 years? show your work. 3. what would be the y-intercept of the graph? what does it represent? 4. after how many years will the amount of cobalt-60 left be 6.25 mg? explain what happens to the cobalt-60 after 50 years? 5. discuss some “real-world” examples and uses of cobalt-60