National Welding Uses Industrial Robots in Some of Its Assembly-Line

Multiple Choice

National Welding uses industrial robots in some of its assembly-line operations. Management has determined that, on average, a robot breaks down after 1,000 hours of use and that the lengths of time between breakdowns are exponentially distributed.
A. What is the probability that a robot selected at random will break down between 300 and 800 hours of use?
Round your answer to two decimal places.
B. What is the probability that a robot will break down after 1,200 hours of use?
Round your answer to two decimal places.

A) a. 0.29, b. 0.3
B) a. 0.61, b. 0.13
C) a. 0.76, b. 0.44
D) a. 0.26, b. 0.61