Selina Concise Mathematicsclass 6 ICSE Solutions Chapter 34 Mean and Median

Selina Concise Mathematicsclass 6 ICSE Solutions – Mean and Median

Selina Concise Mathematicsclass 6 ICSE Solutions – Mean and Median

EXERCISE 34 (A)

Question 1.
Find the mean of :
(i) 7,10, 4 and 17
(ii) 12, 9, 6,11 and 17
(iii) 3, 1, 5, 4, 4 and 7
(iv) 7, 5, 0, 3, 0, 6, 0, 9, 1 and 4
(v) 2.1, 4.5, 5.2, 7.1 and 9.3
(vi) 5, 2.4, 6.2, 8.9, 4.1 and 3.4
Answer:

Question 2.
Find the mean of :
(i) first eight natural numbers
(ii) first six even natural numbers
(iii) first five odd natural numbers
(iv) all prime numbers upto 30
(v) all prime numbers between 20 and 40.
Answer:

(i) The first eight natural numbers are 1, 2, 3, 4, 5, 6, 7, 8

∴Sum of these observations =1+2+3+4+5+6+7+8=36

and, number of their observations = 8

∴Required mean == 4.5

(ii) The first six even natural numbers are 1 = 2, 4, 6, 8, 10, 12

∴Sum of these observations = 2, 4, 6, 8, 10, 12 = 42

and, number of their observations = 6

∴ Required mean == 7

(iii) The first five odd natural numbers are = 1, 3, 5, 7, 9

∴Sum of these observations =1 + 3 + 5 + 7 + 9 = 25

and, number of their observations = 5

∴Required mean == 5

(iv) The all prime numbers upto 30 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29

∴Sum of these observations = 2 + 3 +5 + 7+ 11 + 13 + 17 + 19 + 23 +29 = 129

and, number of their observations = 10

∴Required mean == 12-9

(v) All prime numbers between 20 and 40 are 23, 29, 31, 37

Sum of these observations = 23+29 + 31 + 37 = 120 .

and, number of their observations = 4

120

∴ Required mean == 30

Question 3.

Height (in cm) of 7 boys of a locality are 144 cm, 155 cm, 168 cm, 163 cm, 167 cm, 151 cm and 158 cm. Find their mean height.

Answer:

Sum of the values = Sum of heights

= 144 cm + 155 cm + 168 cm + 163 cm + 167 cm + 151 cm + 158 cm = 1106 cm and Number of values = Number of boys = 7

Question 4.

Find the mean of 35, 44, 31, 57, 38, 29, 26,36, 41 and 43.

Answer:

Sum of the values = 35 + 44 + 31 + 57 + 38 + 29 + 26 + 36 + 41 + 43 = 380
and Number of values = 10

Question 5.

The mean of 18, 28, x, 32, 14 and 36 is 23. Find the value of x. Sum of data

Answer:

Question 6.

If the mean of x, x + 2, x + 4, x + 6 and x + 8 is 13, find the value of x. Sum of data

Answer:

EXERCISE 34 (B)

Question 1.

Find the median of

(i) 21, 21, 22, 23, 23, 24, 24, 24, 24, 25 and 25

(ii) 3.2, 4.8, 5.6, 5.6, 7.3, 8.9 and 91

(iii) 17, 23, 36, 12, 18, 23, 40 and 20

(iv) 26, 33, 41, 18, 30, 22, 36, 45 and 24

(v) 80, 48, 66, 61, 75, 52, 45 and 70

Solution:

Question 2.

Find the mean and the median of :

(i) 1,3,4, 5, 9, 9 and 11

(ii) 10,12, 12, 15, 15, 17, 18, 18, 18 and 19

(iii) 2, 4, 5, 8, 10,13 and 14

(iv) 5, 8, 10, 11,13, 16, 19 and 20

(v) 1.2, 1.9, 2.2, 2.6 and 2.9

(vi) 0.5, 5.6, 3.8, 4.9, 2.7 and 4.4.

Solution: