Suppose that x is a random variable with mean 20 and standard deviation 5. also
suppose that y is a random variable with mean 40 and standard deviation 10. find the
variance and standard deviation of the random variable z for each of the following
cases. be sure to show your work.
(a) z = 2 + 10x.
(b) z = 10x − 2.
(c) z = x + y.
(d) z = x − y.
(e) z = −3x − 2y.

answer: yes youre right.

step-by-step explanation:

answer: option a.

step-by-step explanation:

you know that the quadrilateral opqr ( a four sided figure) is inscribed in circle. this means that all its vertices are on the circle.

then, by definition, the opposite angles of the quadrilateral are supplementary, this means that the sum of their measures is 180 degrees.

you can observe in the figure that the angles ∠opq   and the angle ∠orq   are opposite, therefore:

then, can be used to d to calculate the measure of ∠opq