250 students of class X of a school appeared in a test of 100 marks and the data about the marks secured is as below.
$\begin{matrix} Marks secured & 0 - 20 & 21 - 40 & 41 - 60 & 61 - 80 & 81 - 100 Number of students & 20 & 35 & 65 & 60 & 70 \end{matrix}$

Find the probability of selecting at random, a student who scored

(i) not more than 40
(ii) more than 60
(iii) more than 80 [ 2 MARKS ]

Open in App

Solution

Concept: 1.5 Marks
Solution: 0.5 Marks each

Number of students who didn’t score more than 40 = 20 + 35 = 55
Probability that a student didn’t score more than 40 = $\frac{55}{250}$ = 0.22.
Number of students who scored more than 60 = 60 + 70 = 130
Probability that a student scored more than 60 = $\frac{130}{250}$ = 0.52.
Number of students who scored more than 80 = 70
Probability that a student scored more than 80 = $\frac{70}{250}$ = 0.28.

Suggest Corrections

Similar questions

250 students of class X of a school appeared in a test of 100 marks and the data about the marks secured is as below.
$\begin{matrix} Marks secured & 0 - 20 & 21 - 40 & 41 - 60 & 61 - 80 & 81 - 100 Number of students & 20 & 35 & 65 & 60 & 70 \end{matrix}$

Find the probability of selecting at random, a student who scored

(i) not more than 40
(ii) more than 60
(iii) more than 80 [ 2 MARKS ]

250 students of class X of a school appeared in a test of 100 marks and the data about the marks secured is as below. $\begin{matrix} M a r k s s e c u r e d & 0 - 20 & 21 - 40 & 41 - 60 & 61 - 80 & 81 - 100 N u m b e r o f s t u d e n t s & 20 & 35 & 65 & 60 & 70 \end{matrix}$

Find the probability of selecting at random, a student who scored

(i) not more than 40
(ii) more than 60
(iii) more than 80 [ 2 MARKS ]

$400$ students of class $X$ of a school appeared in a test of $100$ marks in the subject of social
studies and the data about the marks secured is as below :

Marks secured	Number of Students
$0 - 25$	$50$
$26 - 50$	$220$
$51 - 75$	$100$
Above $75$	$30$
Total number of students	$400$

If the result card of a student he picked up at random, what is the probability that the student has secured more than $50$ marks.

Q. 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

250 students of class X of a school appeared in a test of 100 marks and the data about the marks secured is a below

$\begin{matrix} M a r k s s e c u r e d & N u m b e r o f s t u d e n t s 0 - 20 & 20 20 - 40 & 35 40 - 60 & 65 60 - 80 & 60 80 - 100 & 70 \end{matrix}$

Find the modal vlaue of the above data. [2 MARKS]

Join BYJU'S Learning Program