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!!!

answer: city needs 2.4 inches of rainfall more to match the record of 40 inches.

step-by-step explanation:

since we have given that

total annual rainfall a city record = 40 inches

this year, total rainfall recorded = 37.6 inches

number of inches of rainfall   is needed to match the record of 40 inches is given by

hence, city needs 2.4 inches of rainfall more to match the record of 40 inches.