Suppose compact fluorescent light bulbs last, on average, 10,000 hours. the standard deviation is 500 hours. what percent of light bulbs burn out within 11,000 hours?
how do you show your work for this problem. i dont know how to solve it.

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn.if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.

Which of the following circles have their centers on the x-axis? check all that apply.

Frank is lending $1,000 to sarah for two years. frank and sarah agree that frank should earn a real return of 4 percent per year. instructions: a. the cpi (times 100) is 100 at the time that frank makes the loan. it is expected to be 113 in one year and 127.7 in two years. what nominal rate of interest should frank charge sarah?