Assume that when adults with smart phones are randomly selected 46% use them in meetings or classes if 20 adult smartphone users are randomly selected find the probability that exactly 12 of them use their smart phones in meetings or classes

0.0818.

Step-by-step explanation:

This question can be solved using the binomial theorem because the probability of success is fixed.

Total adults = n = 20

Required attempts = r = 12

Probability of success = p = 3/4 = 0.46

Binomial Theorem formula:

P(X=r) = nCr * p^r * (1-p)^(n-r).

Substituting the values:

P(X=12) = 20C12 * 0.46^12 * (1-0.46)^8

P(X=12) = 125970 * 0.46^12 * (0.54)^8 = 0.0818 (to the nearest 3 significant figures).

So the probability that exactly 12 people use their smart phones in meetings or classes out of 20 is 0.0818!!!

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: