Acertain process for removing copper from copper bearing ore had been in use for a period of time, and it is known that this process removes 36 pounds per ton on average. a new process that is supposed to increase the recovered amount is being tested. in a simple random sample of 100 batches of ore, an average of 42 pounds per ton were recovered using the new process. the population of interest in the study is: a. the increase of 6 pounds per ton. b. the miners working with the ore. c. the 100 batches tested. d. ore treated with the new process. e. ore treated with the old process

d. Ore treated with the new process.

Step-by-step explanation:

This is a common practice in statistics, in which we use a sample of a population to infer something about the entire population. We should use a sample of 100.

For example, if we want to know the proportion of residents of Buffalo, New York, who are Bills fans, we are going to take a sample of like, 100 residents, and then use this to estimate for the entire city.

In this problem, we have that:

A new process that is supposed to increase the recovered amount is being tested. In a simple random sample of 100 batches of ore, an average of 42 pounds per ton were recovered using the new process.

So the population of interest is the ore treated with new process. We use a sample of 100 to gather information about the entire population.

So the correct answer is:

d. Ore treated with the new process.

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1