Answer:
1500 students
600 boys
Step-by-step explanation:
40% are boys, so 60% are girls.
Writing a proportion:
900 / 60% = x / 100%
x = 1500
There are 1500 students in the school, which means there are 600 boys in the school.
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.
If you have a graphing calculator one way to know you are right is put the left side in Y1 and the right side in Y2 then hit 2nd trace and intersection then find the intersection and the X value is your answer. If you don't have a graphing calculator then I'm sorry