Answer:
He needs to work for 40 whole hours
Step-by-step explanation:
In this question, we are tasked with calculating the amount a Tv will cost Bob in terms of the number of hours he needs to work.
Let’s look at the total cost he has to pay.
a. $500
b. 8% tax = 8/100 * 500 = $40
c. He is paying 2 bills of $35 each making a total of 2 * $35 = $70
The total amount he is to pay is thus; 500 + 40 + 70 = $610
Let’s look at his income ;
a. Bonus $45
b. Birthday gift $85
The total amount of money he has asides his salary to offset the bill is 45 + 85 = $130
The balance to pay from his salary would be $610 - $130 = $480
The number of hours he has to work since he earns $12 per hour would be 480/12 = 40 hours of work
Answer:
0.0082 = 0.82% probability that he will pass
Step-by-step explanation:
For each question, there are only two possible outcomes. Either the students guesses the correct answer, or he guesses the wrong answer. The probability of guessing the correct answer for a question is independent of other questions. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
![P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}](https://tex.z-dn.net/?f=P%28X%20%3D%20x%29%20%3D%20C_%7Bn%2Cx%7D.p%5E%7Bx%7D.%281-p%29%5E%7Bn-x%7D)
In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.
![C_{n,x} = \frac{n!}{x!(n-x)!}](https://tex.z-dn.net/?f=C_%7Bn%2Cx%7D%20%3D%20%5Cfrac%7Bn%21%7D%7Bx%21%28n-x%29%21%7D)
And p is the probability of X happening.
In this problem we have that:
.
If the student makes knowledgeable guesses, what is the probability that he will pass?
He needs to guess at least 9 answers correctly. So
![P(X \geq 9) = P(X = 9) + P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14)](https://tex.z-dn.net/?f=P%28X%20%5Cgeq%209%29%20%3D%20P%28X%20%3D%209%29%20%2B%20P%28X%20%3D%2010%29%20%2B%20P%28X%20%3D%2011%29%20%2B%20P%28X%20%3D%2012%29%20%2B%20P%28X%20%3D%2013%29%20%2B%20P%28X%20%3D%2014%29)
![P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}](https://tex.z-dn.net/?f=P%28X%20%3D%20x%29%20%3D%20C_%7Bn%2Cx%7D.p%5E%7Bx%7D.%281-p%29%5E%7Bn-x%7D)
![P(X = 9) = C_{14,9}.(0.3)^{9}.(0.7)^{5} = 0.0066](https://tex.z-dn.net/?f=P%28X%20%3D%209%29%20%3D%20C_%7B14%2C9%7D.%280.3%29%5E%7B9%7D.%280.7%29%5E%7B5%7D%20%3D%200.0066)
![P(X = 10) = C_{14,10}.(0.3)^{10}.(0.7)^{4} = 0.0014](https://tex.z-dn.net/?f=P%28X%20%3D%2010%29%20%3D%20C_%7B14%2C10%7D.%280.3%29%5E%7B10%7D.%280.7%29%5E%7B4%7D%20%3D%200.0014)
![P(X = 11) = C_{14,11}.(0.3)^{11}.(0.7)^{3} = 0.0002](https://tex.z-dn.net/?f=P%28X%20%3D%2011%29%20%3D%20C_%7B14%2C11%7D.%280.3%29%5E%7B11%7D.%280.7%29%5E%7B3%7D%20%3D%200.0002)
![P(X = 12) = C_{14,12}.(0.3)^{12}.(0.7)^{2} = 0.000024](https://tex.z-dn.net/?f=P%28X%20%3D%2012%29%20%3D%20C_%7B14%2C12%7D.%280.3%29%5E%7B12%7D.%280.7%29%5E%7B2%7D%20%3D%200.000024)
![P(X = 13) = C_{14,13}.(0.3)^{13}.(0.7)^{1} = 0.000002](https://tex.z-dn.net/?f=P%28X%20%3D%2013%29%20%3D%20C_%7B14%2C13%7D.%280.3%29%5E%7B13%7D.%280.7%29%5E%7B1%7D%20%3D%200.000002)
![P(X = 14) = C_{14,14}.(0.3)^{14}.(0.7)^{0} \cong 0](https://tex.z-dn.net/?f=P%28X%20%3D%2014%29%20%3D%20C_%7B14%2C14%7D.%280.3%29%5E%7B14%7D.%280.7%29%5E%7B0%7D%20%5Ccong%200%20)
![P(X \geq 9) = P(X = 9) + P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) = 0.0066 + 0.0014 + 0.0002 + 0.000024 + 0.000002 = 0.0082](https://tex.z-dn.net/?f=P%28X%20%5Cgeq%209%29%20%3D%20P%28X%20%3D%209%29%20%2B%20P%28X%20%3D%2010%29%20%2B%20P%28X%20%3D%2011%29%20%2B%20P%28X%20%3D%2012%29%20%2B%20P%28X%20%3D%2013%29%20%2B%20P%28X%20%3D%2014%29%20%3D%200.0066%20%2B%200.0014%20%2B%200.0002%20%2B%200.000024%20%2B%200.000002%20%3D%200.0082)
0.0082 = 0.82% probability that he will pass
I think it’s 25....Yeah I’m pretty sure it’s 25
I cant answer if i dont know what math would you mind telling me what math