An oil company conducts a geological study that indicates that an exploratory oil well should have a 20% chance of striking oil. A. What is the probability that the first strike comes on the third well drilled?
B. What is the probability that the third strike comes on the seventh well drilled?C. What is the mean and the variance of the number of bad wells, if the oil company wants toset up three producing wells?

a)  0.128

b)  0.049152

Step-by-step explanation:

a) first strike comes on the third well drilled

=> two non-strikes and a strike

P = (0.8)^2 * (0.2)

= 0.128

b) third strike comes on the seventh well drilled

=> two strikes in first six wells and a strike in seventh

P = 6C2 * (0.2)^2 (0.8)^4 * (0.2)

= 0.049152

the ratio of white tiles to blue tiles is 48: 16. the ratio in it's simplest form is 3: 1.

step-by-step explanation:

ratio: take the first number and add a colon next to it, then add the second number after that. make sure the ratio order matches up with the written problem!

simplest form: we can simplify the ratio 48 : 16 by dividing both terms by the greatest common factor (gcf).

the gcf of 48 and 16 is 16.

divide both terms by 16:

48 ÷ 16 = 3

16 ÷ 16 = 1

reducing to simplest form:

48 : 16 = 3 : 1

step-by-step explanation:

descending order means to order the polynomials from the term with the largest exponent to the term with the smallest exponent.  

therefore, the correct answer is d.