3/47 is a rational number
p/q is a rational number, where p and q are real integers, and q does not equal to 0.
BCD= 120 degrees. explanation: the 4 angles of a parallelogram must equal 360 degrees. so you add all 4 angles & get 6x. you then take that 6 & divide it from 360 (360/6) and get 60. therefore x=60. so then you just multiple BCD (2x) by 60 and you get 120 degrees
Solution: We are given:

Using the empirical rule, we have:
covers 68% of data.
Also the percentage of values below mean = Percentage of values above mean = 50%
Now, let's find the z score for x=20

Therefore, the percentage of values greater than 1 standard deviation above mean 
Expected number of students = 16% of 100 = 16