Respuesta :
The answer is A, 0.057. This one you can solve using logic. D is to low, C is also to low. That leaves A and B. If your rounding to the nearest thousandth C and D don't make to much sense. Looking at it, considering its 7 devices, A makes the most sense. I'll write the math up here later if you want.
Answer:
A. 0.057
Step-by-step explanation:
This problem can be result using a Binomial distribution, in which we have n identical events with a probability p of success.
The probability that x of the n events get success is given by:
[tex]P(x)=nCx*p^{x}*(1-p)^{n-x}[/tex]
Where nCx can be calculate as:
[tex]nCx=\frac{n!}{x!(n-x)!}[/tex]
In this case there a 10 device with a probability 0.9 of function properly and we need to find the probability that 7 of these device function properly, so replacing values, we get:
[tex]P(7)=10C7*0.9^{7}*(1-0.9)^{10-7}[/tex]
P(7)=120*0.478*0.001
P(7)=0.057
Finally the probability, to the nearest thousandth, that 7 of the 10 devices function properly is 0.057