Refer to the below data table and answer the following question.
Marks Number of students
40 and above 25
30 and above 44
20 and above 56
10 and above 86
0 and above 100
How many students have scored marks 20 or more but less than 40?

The data given is in a cumulative form ("and above").
Number of students scoring 20 and above = 56

Number of students scoring 40 and above = 25

To find the number of students who scored 20 or more but less than 40, we subtract the students who scored 40 and above from those who scored 20 and above:

Students (20 to 40)=(Students ≥20)−(Students ≥40)
Students (20 to 40)=56−25=31