Answer:
a
Step-by-step explanation:
Answer: 17.89
Step-by-step explanation:
In binomial distribution, the standard deviation is given by :-

As per given , we have
The number of vouchers in the sample with errors is denoted by x.
p= 0.20 , n = 2000
Then , 

Hence, the standard deviation of x is 17.89.
Answer:
212121.
Step-by-step explanation:
It is odd number so it ends in 1.
There are 3 2's and 3 1's which alternate.
Diivisible by 3 and 9
It is 212121.
(x^2) - 16 / x+4 = (x-4)(x+4) / (x+4) = x-4, x not equal to -4
D is the answer.