The time until failure of an electronic device has an exponential distribution with mean 15 months. If a random sample of five such devices are tested, what is the probability that the first failure among the five devices occurs a after 9 months? b before 12 months?

The label on the car's antifreeze container claims to protect the car between ? 40°c and 125°c. to convert celsius temperature to fahrenheit temperature, the formula is c = 5 over 9 (f ? 32). write and solve the inequality to determine the fahrenheit temperature range at which this antifreeze protects the car. ? 40 > 5 over 9 (f ? 32) > 125; ? 40 > f > 257 ? 40 < 5 over 9 (f ? 32) < 125; ? 40 < f < 257 ? 40 < 5 over 9 (f ? 32); ? 40 < f 5 over 9 (f ? 32) < 125; f < 257

11. a particular type of cell doubles in number every hour. which function can be used to find the number of cells present at the end of h hours if there are initially 4 of these cells? a. n = 4 ()" b. n = 4(2)" c. n = 4 + (2)" din = 4 +"

Jose predicted that he would sell 48 umbrellas. he actually sold 72 umbrellas. what are the values of a and b in the table below? round to the nearest tenth if necessary