Answer:
560 students
Step-by-step explanation:
400x1.4=560
Answer: Mean = 5.25
Variance = 1.3125
Standard deviation = 1.456
Step-by-step explanation:
The mean and variance of a binomial distribution with parameters n (number of trials) and p ( the probability of getting success in each trial) is given by :-

Given : The total number of enter a clothing store : n=7
The probability of a customer making a purchase= 0.75
Now,

The answer should be -192. I could explain in the comments if you would like. :)
Is it 4x squared? if so the answer would be A