Answer:
D. a = 60 and b = 58.8
Step-by-step explanation:
Z-score:
In a set with mean
and standard deviation
, the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Z-score for data point a is 0.
This means that a is the mean, that is, a = 60.
The z-score for data point b is -0.4.
This means that b must be a value below the mean, that is, a value below 60.
The option that satisfies a = 60 and b < 60 is option D, which is the answer.
Answer:
She did not qualify the exam.
Step-by-step explanation:
Given data
Total no of question in a test = 20
No. of question answered correctly = 16
Percentage of question answered correctly

But in order to get in the exam the student must have to score at least 90 %. But she got only 80 % so she did not qualify the exam.
2 ratio 3,so, 2+3=5
15/5=3 add and then division
Class ratio of girls to boys is 3:5
So there are 3 girls and 5 boys in 8 students
If there are 32 students, then 3/(3+5) * 32 = 12 girls, and 5/(3+5) * 32 = 20 boys
Hope it helps you?