Solution: The given random experiment follows Binomial distribution with 
Let 
be the number of adults who use their smartphones in meetings or classes.
Therefore, we have to find:
We know the binomial model is:
Therefore, the probability that fewer than 3 of them is 0.1111
A because D is less than or equal to, C is saying that 9 is bigger than 12 and B is incorrect because the sign is going to point towards the bigger number
Check if you can write an equation relating the term number to the actual value
n1=3
n2=10 = 3+7
n3= 17 = n2+7 = n1+7+7 = n1 +2*7
n4= 24 = n1+3*7
so you will notice a pattern
for the x-th term
n_x =3+(x-1)*7
the 50th term would be n_50 = 3+(50-1) * 7
Answer:
Thank you have fun in quarantine
