The lifetime of a certain brand of battery is normally distributed with a mean value of 9 hr and a standard deviation of 0.8 hr when it is used in a particular DVD player. Suppose that two new batteries are independently selected and put into the player. The player stops functioning as soon as one of the batteries fails. (Round your answers to four decimal places.) Required:
a. What is the probability that the player functions for at least 8 hr?
b. What is the probability that the cassette player works for at most 11 hr?
c. Find a number z* such that only 10% of all cassette players will function without battery replacement for more than z* hr.

The probability that an adult possesses a credit card is .70. a researcher selects two adults at random. by assuming the independence, the probability that the first adult possesses a credit card and the second adult does not possess a credit card is:

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?

Consider the following geometry problems in 3-space enter t or f depending on whether the statement is true or false. (you must enter t or f -- true and false will not work.) f equation editorequation editor 1. a plane and a line either intersect or are parallel t equation editorequation editor 2. two planes parallel to a third plane are parallel f equation editorequation editor 3. two lines either intersect or are parallel f equation editorequation editor 4. two planes orthogonal to a third plane are parallel f equation editorequation editor 5. two planes orthogonal to a line are parallel f equation editorequation editor 6. two planes either intersect or are parallel f equation editorequation editor 7. two lines orthogonal to a third line are parallel t equation editorequation editor 8. two lines parallel to a third line are parallel t equation editorequation editor 9. two planes parallel to a line are parallel f equation editorequation editor 10. two lines parallel to a plane are parallel f equation editorequation editor 11. two lines orthogonal to a plane are parallel