Answer:
For the average to be above 90, the marks in the fourth paper should be MORE THAN 92.
Step-by-step explanation:
The score of students in last 3 exams = 89 , 87 and 92
Let us assume the marks scored by the student in last exam = k
The average of marks should be above 90.
Now, 
Sum of all 4 paper's marks = 89 + 87 + 92 + k = 268 + k
Also, 90 < Average
Hence,for the average to be above 90, the marks in the fourth paper should be MORE THAN 92.
C. y=2(1/4)^x
B is just a linear functions and the other two aren't exponential functions
59 cans ... she counting up by 5s so multiply 5 x 10
I made a probability tree. Pls. see attachment.
Based on the probability tree I made, below are the probabilities
Probability of a student accepted at both Dartmouth and Harvard is:
50% x 40% = 20%
Probability of a student accepted at Dartmouth but not Harvard is:
50% x 60% = 30%
Probability of a student not accepted at Dartmouth but accepted in Harvard is:
50% x 20% = 10%
Probability of a student not accepted in both schools is:
50% x 80% = 40%
As you can see, these probabilities total 100%
