Answer:
a) P = 0.039
b) The expected number of days is 10 days.
Step-by-step explanation:
The most appropiate distribution to use in this case is the geometric distribution, in order to calculate the probability of a success after k failure trials.
The probability of success, as each of the 10 products are assumed to have fair probabilities, is:

Then, the probability that our product is not selected any given day is:

a) The probability that exactly this product is selected exactly 10 days from now is the probability that is not selected (probbility q) for the next 9 days and selected (probability p) at the 10th day:

b) The expected number of days is calculated as:

Adiya’s method is not correct. To form a perfect square trinomial, the constant must be isolated on one side of the equation. Also, the coefficient of the term with an exponent of 1 on the variable is used to find the constant in the perfect square trinomial. Adiya should first get the 20x term on the same side of the equation as x2. Then she would divide 20 by 2, square it, and add 100 to both sides.
Answer:
Quadrant I and III
Step-by-step explanation:
The coordinate (3,9) is all positive, therefore it lies in quadrant I.
The coordinate (-3,-9) is all negative, therefore it lies in quadrant III.