Question

: Find the number of students who obtained marks between 60 and 70 from the following

Answer 1

Answer:

(i) Total number of student in a class, n(S)=90

The number of student obtained less than 20% marks lies in the interval 0−20, i.e., n(E)=7

∴ The probability, that a student obtained less than 20% marks in the methematics test

=n(E)n(S)=790

(ii) The number of students obtained marks 60 or above lies in the marks interval 60-70 and 70-above, i.e., n(F)=15+8=23.

∴ The probability that a student obtained marks 60 or above =n(F)n(S)=239