Answer:
The mathematical expectation of a student who purchases 10 tickets is -$39.65.
Step-by-step explanation:
A student that purchases 10 tickets out of 2900 has a probability of winning the cruise that can be calculated as:

Each ticket cost $5, so he has spent $50 for the 10 tickets.
Then, the expected value of this operation is equal to the expected value of the earnings (probability of winning the prize multiplied by the value of the prize), minus the costs:

The mathematical expectation of a student who purchases 10 tickets is -$39.65.
The standard form: Ax + By = C
3x - y = -6 YES - A = 3, B = -1, C = -6
3x + y = 6 YES - A = 3, B = 1, C = 6
x + 6y = 9 YES - A = 1, B = 6, C = 9
x - 6y = -9 YES - A = 1, B = -6, C = -9
Answer:
60°
Step-by-step explanation:
The sum of angles in a triangle is 180°.
∠R + 88° + 32° = 180°
∠R = 60° . . . . . . subtract 120° from both sides of the equation
Answer:
years worked: 14
at least 10 years: 73%
Step-by-step explanation:
The mean is found by adding the years of service and dividing by the number of employees. The total years of service is 417, so the average is ...
average years worked = 417/30 = 13.9 ≈ 14 . . . years
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The percentage of employees that have worked there at least 10 years is found by counting the number with 10 or more years of service and dividing that count by the total number of employees. The result is then expressed as a percentage.
(10 years or over)/(total number) = 22/30 = 0.73_3 (a repeating decimal) ≈ 73%
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Comment on the working
A spreadsheet can be helpful for this. It has a function that can calculate the mean for you. Sorting the years of service into order can make it trivially easy to count the number that are 10 or more, or you can write a function that will do the count for you. (Also, less than 10 means the years are a single digit. There are 8 single-digit numbers in your list.) The hard part is copying 30 numbers without error.
Answer:
the answer is 397.32
Step-by-step explanation:
333.75 ÷ 5.25 = 397.32