An electronic switch has a constant failure rate of 10-3 per hour. a) What is the expected life of the switch? b) What is the standard deviation of the switch? c) What is the probability that the switch will last between 1200 and 1400 hours?

Candice uses the function f(t)=t+100−−−−−−√ to model the number of students in her after-school program. the variable t represents days and f(t) represents the number of students. how many days does it take for there to be 15 students in her program? a. 225 days b. 125 days c. 325 days d. 115 days