Answer:
0.0111% probability that he answers at least 10 questions correctly
Step-by-step explanation:
For each question, there are only two outcomes. Either it is answered correctly, or it is not. The probability of a question being answered correctly is independent from other questions. 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.
A multiple-choice examination has 15 questions, each with five answers, only one of which is correct.
This means that 
What is the probability that he answers at least 10 questions correctly?









0.0111% probability that he answers at least 10 questions correctly
Answer:
And the 96% confidence is given by (110.06; 117.34)
Step-by-step explanation:
Information given
represent the sample mean
population mean (variable of interest)
s=9.1 represent the sample standard deviation
n=29 represent the sample size
Confidence interval
The confidence interval for the mean is given by the following formula:
(1)
The degrees of freedom are given by:
The Confidence is 0.96 or 96%, the significance is
and
, and the critical value would be
Replacing the info we got:
And the 96% confidence is given by (110.06; 117.34)
Answer:
perimeter is 12x-6
Step-by-step explanation:
perimeter is the sum of all sides
3(x+2) + 2x+11 + 7x-23
distribute the 3 in the first term, then combine 'like terms'
3x+6 + 2x+11 + 7x-23
3x+2x+7x + 6+11+(-23)
12x-6