A manufacturer of four-speed clutches for automobiles claims that the clutch will not fail until after 50,000 miles. A random sample of 10 clutches has a mean of 58,750 miles with a standard deviation of 3775 miles. Assume that the population distribution is normal. Does the sample data suggest that the true mean mileage to failure is more than 50,000 miles. Test at the 5% level of significance. What is the value of the hypothesized mean

Which answer is the solution set to the inequality |x|< 9? a. x< -9 or x> 9 b. x> -9 and x< 9 c. x> -9 or x< 9 d. x< 9 and x< 9

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

Factor and solve to find roots x squared -x - 90 =0