CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Marks obtained by 90 students of Class IX in a test are given below:
Marks 0−20 20−40 40−60 60−80 80−100
No. of students 8 15 32 26 9
Out of these students one is chosen at random. Find the probability that the chosen student obtains
(i) less than 20% marks
(ii) 80% or more marks
(iii) 60% or more marks

Open in App
Solution

Total number of students = 90
(i) Number of students who scored less than 20% marks = 8
Let E1 be the event that selected student got less than 20% mark .
∴ P(E1) = 890 = 445
(ii) Number of students who scored 80% marks or more = 9
Let E2 be the event that selected student got 60% marks or more .
P(E2) = 990 = 110
(iii) Number of students who scored 60% marks or more = (26 + 9 ) = 35
Let E3 be the event that selected student got 60% marks or more.
∴​ P(E3) = 3590 = 7181990

flag
Suggest Corrections
thumbs-up
2
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Introduction to Probability
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon