Refer to Table 14.7, Chapter $ 14 . $
(i) Find the probability that a student obtained less than $ 20 \% $ in the mathematics test.
(ii) Find the probability that a student obtained marks 60 or above.

AcademicMathematicsNCERTClass 9

To do:

We have to find

(i) The probability that a student obtained less than \( 20 \% \) in the mathematics test.
(ii) The probability that a student obtained marks 60 or above.

Solution:

MarksNumber of students
0-207
20-3010
30-4010
40-5020
50-6020
60-7015
70-above8
Total90

The total number of students $=90$

We know that,

Probability of an event=$ \frac{\text { Number of favourable outcomes }}{\text { Total number of outcomes }}$

Therefore,

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

This implies,

The probability that a student obtained less than $20 \%$ in the mathematics test $= \frac{7}{90}$

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

$= 23$

This implies,

The probability that a student obtained marks 60 or above $= \frac{23}{90}$

raja
Updated on 10-Oct-2022 13:47:37

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