D, square root of 75= 5 square root 3
For 1 hour:
- Jennifer can clean 1/2 of her room;
- John cal clean 1/5 of her room.
Both can clean: 1/2 + 1/5 = 5/10 + 2/10 = 7/10
1 hour -------- 7/10
x hours---------- 1
x = 1 : 7/10 = 10/7 h = 1.42857 h ( or 1 h 25 min 43 s )
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
Answer:
8 and -4
Step-by-step explanation:
8*-4=-32
8+(-4)=4