Question

The heights of the students of a class is measured and recorded as given below :-

A student is selected at random. Find the probability that height of the student is :-

( i ) More than 135 cm
( ii ) At least 145 cm
( iii ) Less than 130 cm
( iv ) 125 cm or more but less than 140 cm​

Answer 1

Hi mate this is a veryyyyyy simple question ok I will give the correct answer

(i) = 3,5,9,8

(ii) = 5,3,11,7,7

(iii) = 7,7

(iv) = 7,11,3,6

Answer 2

Answer:

(i) More than 135cm = $\frac{1}{2}$

(ii) At least 145 cm = $\frac{17}{50}$

(iii) Less than 130 cm = $\frac{7}{25}$

(iv) 125 cm or more but less than 140 cm = $\frac{21}{50}$

Step-by-step explanation:

Total number of students = 7+7+11+3+5+9+8 = 50

(i) More than 135cm

$P(X > 135)=\frac{3+5+9+8}{50}\\ P(X > 135)=\frac{25}{50}\\ P(X > 135)=\frac{1}{2}$

(ii) At least 145 cm

$P(X\geq 145) = \frac{9+8}{50}\\P(X\geq 145) =\frac{17}{50}$

(iii) Less than 130 cm

$P(X < 130) = \frac{7+7}{50}\\P(X < 130) = \frac{14}{50} = \frac{7}{25}$

(iv) 125 cm or more but less than 140 cm

$P(125 < X < 140) = \frac{7+11+3}{50}\\P(125 < X < 140) =\frac{21}{50}$

So we get the answers as :

(i) More than 135cm = $\frac{1}{2}$

(ii) At least 145 cm = $\frac{17}{50}$

(iii) Less than 130 cm = $\frac{7}{25}$

(iv) 125 cm or more but less than 140 cm = $\frac{21}{50}$