Question

6. The marks (out of 50) obtained by a group of
students in a mathematics test are :
45, 46, 40, 45, 49, 38, 46, 48, 30, 22
Find :
(i) Highest and lowest marks obtained by
the students.
(ii) Range of the marks obtained.
(iii) Mean marks obtained by the group.
(iv) How many students have marks less
than the mean marks?​

Answer 1

1} highest 49 and lowest 22

2} x

3} x

4} x

x means I don't know

!!!!

Answer 2

Given:-

• The marks obtained in a mathematics for students are

☆ 45, 46 , 40 , 45 , 49 , 38 , 46 , 48 , 30 , 22

To find :-

• (i) Highest and lowest marks obtained by
• the students.
• (ii) Range of the marks obtained.
• (iii) Mean marks obtained by the group.
• (iv) How many students have marks less
• than the mean marks?

Solution:-

Question - 1

Data :- 45, 46, 40, 45, 49, 38, 46, 48, 30, 22

Least marks :- 22

Highest marks :- 49

Question- 2

$\bigstar \underline{\boxed{ \sf{Range = Highest\: Value - Lowest \: value }}}$

So,

• Highest value is 49
• Lowest value is 22

Range = Highest value - Lowest value

Range = 49 - 22

Range = 27

Question- 3 :-

$\bigstar \underline{\boxed{ \sf{Mean = \dfrac{Sum\:of\:observations}{No\:of\:observations}}}}$

So,

Sum of observations = 45 + 46 + 40 + 45 + 49 + 38 + 46 + 48 + 30 + 22

Sum of observations = 409

No.of observations = 10

$\bigstar \underline{\boxed{ \sf{Mean = \dfrac{Sum\:of\:observations}{No\:of\:observations}}}}$

$= \dfrac{409}{10}$

$= 40.9$

So, mean of the data is 40.9

Question-4 :-

How many students have marks less

than the mean marks?

Since mean marks is 40.9 So,

• 45>40.9
• 46>40.9
• 40< 40.9
• 49>40.9
• 38< 40.9
• 46> 40.9
• 48 > 40.9
• 30< 40.9
• 22<40.9

So, less than 40.9 are 22, 30 , 38 , 40

So, 4 students have marks less than the mean marks