Question 6 (i)
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few students got under 20 marks and a few got 70 marks or above.So she decided to group them into intervals of varying sizes as follows : 0−20,20−30…60−70,70 − 100. Then she formed the following table:
$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t 0 - 20 & 7 20 - 30 & 10 30 - 40 & 10 40 - 50 & 20 50 - 60 & 20 60 - 70 & 15 70 - a b o v e & 8 T o t a l & 90 \end{matrix}$
(i) Find the probability that a student obtained less than 20% in the mathematics
test.

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Solution

Total number of students = 90
(i) Number of students getting less than 20 % marks in the test = 7
Hence, required probability, $P = \frac{7}{90}$

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Question 6 (i)
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few students got under 20 marks and a few got 70 marks or above.So she decided to group them into intervals of varying sizes as follows : 0−20,20−30…60−70,70 − 100. Then she formed the following table:
$\begin{matrix} Marks & Number of student 0 - 20 & 7 20 - 30 & 10 30 - 40 & 10 40 - 50 & 20 50 - 60 & 20 60 - 70 & 15 70 - a b o v e & 8 Total & 90 \end{matrix}$
(i) Find the probability that a student obtained less than 20% in the mathematics
test.

Question 6 (ii)
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few Students got under 20 marks and a few got 70 marks or above.So she decided to Group them into intervals of varying sizes as follows : 0−20,20−30…60−70,70 − 100. Then she formed the following table:
$\begin{matrix} Marks & Number of student 0 - 20 & 7 20 - 30 & 10 30 - 40 & 10 40 - 50 & 20 50 - 60 & 20 60 - 70 & 15 70 - a b o v e & 8 Total & 90 \end{matrix}$
(ii) Find the probability that a student obtained marks 60 or above.

Marks	Number of Students
$0 - 20$	$7$
$20 - 30$	$10$
$30 - 40$	$10$
$40 - 50$	$20$
$50 - 60$	$20$
$60 - 70$	$15$
$70 -$ Above	$8$
Total	$90$

A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performance, she found that a few students got, under 20 marks and a few got 70 marks or above. So she decided to group them into intervals of varying sizes as follows:

0 - 20, 20 - 30. . . ., 60 - 70, 70 - 100

Then she formed the following table.
(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.

Question 6 (i)
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few students got under 20 marks and a few got 70 marks or above.So she decided to group them into intervals of varying sizes as follows : 0−20,20−30…60−70,70 − 100. Then she formed the following table:
$\begin{matrix} Marks & Number of student 0 - 20 & 7 20 - 30 & 10 30 - 40 & 10 40 - 50 & 20 50 - 60 & 20 60 - 70 & 15 70 - a b o v e & 8 Total & 90 \end{matrix}$
(i) Find the probability that a student obtained less than 20% in the mathematics
test.

Q. Question 6 (ii)
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few Students got under 20 marks and a few got 70 marks or above.So she decided to Group them into intervals of varying sizes as follows : 0−20,20−30…60−70,70 − 100. Then she formed the following table:

\begin{matrix} M a r k s & N u m b e r o f s t u d e n t 0 - 20 & 7 20 - 30 & 10 30 - 40 & 10 40 - 50 & 20 50 - 60 & 20 60 - 70 & 15 70 - a b o v e & 8 T o t a l & 90 \end{matrix}

(ii) Find the probability that a student obtained marks 60 or above.

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Total number of students = 90 (i) Number of students getting less than 20 % marks in the test = 7 Hence, required probability, P=790

Total number of students = 90
(i) Number of students getting less than 20 % marks in the test = 7
Hence, required probability, $P = \frac{7}{90}$