Using the hypergeometric distribution, it is found that there is a 0.0273 = 2.73% probability that the third defective bulb is the fifth bulb tested.
In this problem, the bulbs are chosen without replacement, hence the <em>hypergeometric distribution</em> is used to solve this question.
<h3>What is the hypergeometric distribution formula?</h3>
The formula is:


The parameters are:
- x is the number of successes.
- N is the size of the population.
- n is the size of the sample.
- k is the total number of desired outcomes.
In this problem:
- There are 12 bulbs, hence N = 12.
- 3 are defective, hence k = 3.
The third defective bulb is the fifth bulb if:
- Two of the first 4 bulbs are defective, which is P(X = 2) when n = 4.
- The fifth is defective, with probability of 1/8, as of the eight remaining bulbs, one will be defective.
Hence:


0.2182 x 1/8 = 0.0273.
0.0273 = 2.73% probability that the third defective bulb is the fifth bulb tested.
More can be learned about the hypergeometric distribution at brainly.com/question/24826394
The surface area of triangular prism is 117.12 mm²
<u>Explanation:</u>
Base side, a = 9 mm
Base side, b = 6.6 mm
Base side, c = 5.2 mm
Height, h = 4 mm
Total surface area = ?
We know,
Surface area, A = 2 Ab ( a+b+c) h
Ab = √s(s-a) (s-b) (s-c)
s = a+b+c/2
Solving for A
A = ah + b h + ch + 1/2 √ -a⁴ + 2(ab)² + 2(ac)² - b⁴ + 2 (b c)² - c⁴
A = 9.4 + 6.6 X 4 + 5.2 X 4 + 1//2 √ -9⁴ + 2(9 X 6.6)² + 2(9 X 5.2)² - (6.6)⁴ + 2 (6.6 X 5.2)² - (5.2)⁴
A = 117.12 mm²
Therefore, the surface area of triangular prism is 117.12 mm²