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 radius of the cylinder's base is 8, so the volume of the cylinder is

(using the approximation of

).
The sphere has radius 6, so the volume of the sphere is

.
The volume of the shaded region is the difference between the two: 3617.28 - 904.32 = 2712.96. Rounded to the nearest integer gives an answer of 2713.
Answer: 12+4+4
Step-by-step explanation:
Because if you add those together you get 20 miles per hour
9 is the answer for that problem