Selina solutions concise maths class 9 icse Solutions for Chapter 19 chapter 19 mean and median

Exercises in Chapter 19 chapter 19 mean and median Grade 9

Exercise 19(A)

Exercise 19(B)

Questions in Exercise 19(A)

Find the mean of the first six natural numbers.

Find the mean of the first ten odd natural numbers.

Find the mean of all factors of 10.

Find the mean of x + 3, x + 5, x + 7, x + 9 and x + 11.

The mean of 5 numbers is 18. If one number is excluded, the mean of the remaining number becomes 16. Find the excluded number.

The mean of 200 items was 50. Later on, it was discovered that two items were misread as 92 and 8 instead of 192 and 88. Find the correct mean.

Find x if 9, x, 14, 18 x, x, 8, 10 and 4 have a mean of 11

Questions in Exercise 19(B)

Find the median of:

(i) 25, 16, 26, 16, 32, 31, 19, 28 and 35

(ii) 241, 243, 347, 350, 327, 299, 261, 292, 271, 258 and 257

(iii) 63, 17, 50, 9, 25, 43, 21, 50, 14 and 34

(iv) 233, 173, 189, 208, 194, 204, 194, 185, 200 and 220.

In 10 numbers, arranged in increasing order, the 7th number is increased by 8, how much will the median be changed?

Out of 10 students, who appeared in a test, three secured less than 30 marks, and 3 secured more than 75 marks. The marks secured by the remaining 4 students are 35, 48, 66, and 40. Find the median score of the whole group.

The median of observations 10, 11, 13, 17, x + 5, 20, 22, 24 and 53 (arranged in ascending order) is 18; find the value of x.

The following observations have been arranged in ascending order. If the median of the data is 78, find the value of x.

44, 47, 63, 65, x + 13, 87, 93, 99, 110.

The following observations have been arranged in ascending order. If the median of these observations are 58, find the value of x.

24, 27, 43, 48, x - 1, x + 3, 68, 73, 80, 90

Find the mean of the following data: 30, 32, 24, 34, 26, 28, 30, 35, 33, 25

(i) Show that the sum of the deviations of all the given observations from the mean is zero.

(ii) Find the median of the given data.

The mean of x, x + 2, x + 4, x + 6 and x + 8 is 11, find the mean of the first three observations.

Find the mean and median of all the positive factors of 72.

The average of n numbers x1, x2, x3 ….. xn is A.

If x1 is replaced by (x+ α) x1, x2, is replaced by (x+ α)x2 and so on. Find the new average.

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Chapters in this book

Chapter 1- Rational and Irrational Numbers

Chapter 2- Compound Interest [Without Using Formula

Chapter 3- Compound Interest [Using Formula

Chapter 4- Expansions

Chapter 5- Factorisation

Chapter 6- Simultaneous Equations

Chapter 7- Indices [exponents]

Chapter 8- Logarithms

Chapter 9- Triangles [Congruency in Triangles]

Chapter 10- Isosceles Triangle

Chapter 11- Inequalities

Chapter 12- Mid-Point and Its Converse

Chapter 13- Pythagoras Theorem

Chapter 14- Rectilinear Figures

Chapter 15- Construction of Polygons

Chapter 16- Area Theorems

Chapter 17- Circles

Chapter 18- Statistics

Chapter 19- Mean and Median

Chapter 20- Area and Perimeter of Plane Figures

Chapter 21- Solids

Chapter 22- Trigonometrical Ratios

Chapter 23- Trigonometrical Ratios of Standard Angles

Chapter 24- Solution Of Right Triangles

Chapter 25- Complementary angles

Chapter 26- Co-ordinate Geometry

Chapter 27- Graphical Solution

Chapter 28- Distance Formula