Answer:
Step-by-step explanation:
The system of equations (a) is the correct one for this situation. We must now solve this system for x and y, which are the unit costs.
Multiplying the 2nd equation by (-3/2) yields -12x - 18y = -168.
Now eliminate x by combining the two equations
12x + 5 y = 116
-12x -18y = - 168
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-13y = -52, or y = 4.
If y = 4 then 12x + 5y = 116, or
12x +5(4) = 116, or
12x + 20 = 116, or
12x = 96, or x = 8
Roller pens are $8/dozen and ball point pens are $4 per dozen.
The answer is 16/15, don’t ask ok, used a calculator
Using sampling concepts, it is found that the sampled is biased because only parents who attend the school's musical show are surveyed, hence they are not very likely to support the decrease, and the population proportion should be greater than the one found in the show.
<h3>How are samples classified?</h3>
Samples may be classified as:
- Convenient: Drawn from a conveniently available pool.
- Random: All the options into a hat and drawn some of them.
- Systematic: Every kth element is taken.
- Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.
- Stratified: Also divides the population into groups. Then, a equal proportion of each group is surveyed.
A sample has to take into account all aspects of the population, otherwise it is biased. In this problem, either people support the decrease, or they do not. Only people that went to the show were surveyed, that is, people who are unlikely to support the decrease, which generates bias, as the population proportion should be greater than the one found in the show.
More can be learned about sampling concepts at brainly.com/question/25122507
No clue how many decimal places you need, but the answer should be 1.1283 cm