ANSWER
The correct answer is option B
EXPLANATION
The equations are
and
When we multiply the second equation by , we obtain;
When we combine this new equation with equation (1).
We can see that has been eliminated from the equation.
We can then, solve for and then substitute the result in to any of the equations to find
.
Hence the correct answer is option B
Using addition of variables, it is found that the mean of S is of 73 and the standard deviation is of 8.5.
<h3>What happens to the mean and the standard deviation when two variables are added?</h3>In this problem, for variables A and B, we have that:
Variable S is the sum of A and B, hence:
The mean of S is of 73 and the standard deviation is of 8.5.
More can be learned about addition of variables at brainly.com/question/26156502