Using the exponential distribution, it is found that there is a 0.3297 = 32.97% probability that a randomly selected part will fail in less than 20 hours.
<h3>Exponential distribution</h3>
The exponential probability distribution, with mean m, is described by the following equation:

In which
is the decay parameter.
The probability that x is lower or equal to a is given by:

Which has the following solution:

In this problem, the mean and the decay parameter are, respectively, given by:
.
The probability that a randomly selected part will <u>fail in less than 20 hours</u> is given by:

0.3297 = 32.97% probability that a randomly selected part will fail in less than 20 hours.
More can be learned about the exponential distribution at brainly.com/question/18596455
Answer:
B
Step-by-step explanation:
First I would find the base, which is a square so 10x10=100
then find the triangle (a=1/2bh) a=1/2(12)(10) a=1/2(120) a=60
since there are four triangle sides do 60x4 which equals 240, so then add the sides to the base 100+240=340, the answer is A
Find the area of each triangle then and them together, so:
1/2(15×8) =60
plus
1/2(15×8) =60
plus
1/2(23×8)=92
plus
1/2(23×8)=92
60+60+92+92=304
304 is the total area.