Refer to Table 14.7, Chapter 14.

Total number of students = 90

(i) Number of students obtained less than 20% in the mathematics test = 7

Hence,

Probability of students obtained less than 20% in mathematics test will be,

= No. of student obtained less than 20% in the mathematics test/Total no. of students

= 7/90

(ii) Number of students obtained marks 60 or above = 15 + 8

= 23

Hence,

Probability of students obtained marks 60 or above will be

= No. of student obtained marks 60 or above in the mathematics test/Total no. of students

23/90