Data can be on a graph like if the weather increase 2 degrees
Answer:
16.78% probability that exactly 12 of them use their smartphones in meetings or classes.
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they use their smartphone in meetings or classes, or they do not. The probability of a person using their phone in meetings or classes is independent of any other person. 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.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
64% use them in meetings or classes.
This means that 
20 adult smartphone users are randomly selected
This means that 
Probability that exactly 12 of them use their smartphones in meetings or classes.
This is P(X = 12).


16.78% probability that exactly 12 of them use their smartphones in meetings or classes.
Answer:
Depends on which place you're rounding to:
Step-by-step explanation:
Rounded to the tenths place (one number after the decimal point):
x = -6.6, -9.4
Rounded to the hundredths place (two numbers after the decimal place):
x = -6.59, -9.41
Rounded to the thousandths place (three numbers after the decimal place):
x = -6.586, -9.414
I don't think you'd need to round to the ten-thousandths place. If you do lemme know and I'll edit my answer. But you should know if the next digit is 5 or greater like in 15 you'd round up. If it's less than 5, you round down.
15.17% is equal to .1517 (just move the decimal to the left twice)
160 km - 100%
100%+30%=130%
160*130%:100%=208 (km) - <span>the number sought</span>