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.
I assume it is the last one, 3n^2, because the degree is the exponent, which is two and the three is the coefficient, which is next to the variable, plus it is a monomial, so there is only one term, eliminating the first two, the third one is just reversed. Therefore, the answer should be the last one. Hope this helps. :)
Answer:
Angle A: 45, Angle B: 110, and Angle C: 25.
Step-by-step explanation:
A triangle is 180 degrees total. One angle is 25 degrees. 180- 25 leaves us with 155 degrees. We know that one angle is more than 65 degrees. 155-65 is 90. 90/2 is 45. Therefore, x= 45. Angle A: 45, Angle B: 110, and Angle C: 25. We can double check our work by adding 45+110+25= 180