and 
There are 6 possible outcomes when rolling a die, 1, 2, 3, 4 , 5, 6
A
numbers less than 4 are 1, 2, 3
P( number less than 4 ) =
= 
B
numbers greater than 4 are 5, 6
P( number greater than 4 ) =
= 
Answer:
look at the picture i have sent
The unknown term is 22.6
28.9
26.8
24.7
22.6
20.5
As you can see, the numbers after the decimal point descends by 1 point. 9 , 8 , 7 , 6 , 5
While the numbers before the decimal point descends by 2 points, 28 , 26 , 24 , 22 , 20
a)
because it is equal to the area of the shaded region between X=4 and X=6, and the probability that X falls within some interval is given by the area under the PDF.
b)
because the shaded region is a rectangle of height 1/5 (by virtue of X following a uniform distribution over the interval [2, 7], which has length 5).