Average

Q.

$\frac{1}{6}$ of the class students are above average$,\frac{1}{4}$ are average and rest are below average. If there are $48$ students in all, how many students are below average in the class$?$

Q. Question 11
The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is:

A) 28
B) 30
C) 35
D) 38

Q. Find the average of the prime numbers between 1 to 20.

1. 9.6
2. 9.5
3. 9.2
4. 9.4

Q. Find the difference between the arithmetic means of all even and odd numbers between 50 and 60.

1. 0
2. 2
3. 1
4. 3

Q.

Organize the following marks in a class assessment, in a tabular form. $4,6,7,5,3,5,4,5,2,6,2,5,1,9,6,5,8,4,6,7$

(i) Which number is the highest?

(ii) Which number is the lowest?

(iii) What is the range of the data?

(iv) Find the arithmetic mean.

Q. The mean of six numbers is 32. If one of the number is removed, the mean is reduced by 2. Find the excluded number.

1. 30
2. 34
3. 42
4. 40

Q.

Find the mean of all prime numbers between $20$ and $40$

Q. If the mean of 9 numbers is 45 , then find the sum of all numbers.

1. 505
2. 605
3. 405
4. 305

Q.

Find the mean of following data :

18 , 33 , 30 , 21 and 13 .

Also find the sum of deviation of this data from the mean

1. (i) 23 (ii) 0

2. (i) 22 (ii) -23

3. (i) -23 (ii) 23

4. (i) 25 (ii) -1

Q. The production of soyabean per acre, in quintal obtained by 9 farmers in Rajapur, is given below. 7, 7.5, 8, 6, 5.5, 7.5, 5, 8, 4

1. 5.5
2. 6
3. 6.4
4. 6.5

Q.

Find the mean weight from the following table.

Weight (kg)	29	30	31	32	33
No. of children	02	01	04	03	05

Q.

The average of the first$20$ results is$20$ and that of the next$30$ results is$30$. What is the average of all $50$results?

1. $26$

2. $25$

3. $24$

4. $50$

Q. Find the value of mean when $\sum f_i{x}_i=50$ and N = 10.

1. 10
2. 15
3. 5
4. 20

Q. The number of children in 25 families are recorded as 2, 2, 3, 1, 4, 2, 1, 3, 1, 3, 1, 4, 2, 3, 1, 2, 1, 3, 4, 1, 2, 1, 2, 3, 1.
Calculate mean of the data.

1. 1.12
2. 2.12
3. 2
4. 3

Q. Arithmetic mean of a given frequency table depends on _______.

1. frequencies of the scores only
2. the scores only
3. both scores and its frequencies
4. None of the above

Q. The average of 5 numbers is 50. The number 40 was incorrectly written as 60 while calculating. Find the correct average.

1. 36
2. 56
3. 46
4. 66

Q. There are four children A, B, C and D. A has 6 chocolates, B has 7 chocolates, C has 8 chocolates and D has 10 chocolates. Which of these children has the average number of chocolates?

1. A
2. B
3. C
4. D

Q.

From an India- Pakistan ODI series, we have a comparison of scores between Sachin Tendulkar and Inzamam-ul-haq.

$$\begin{array}{ccc}\text{ODI}& \text{Sachin Tendulka}r& \text{Inzamam-ul-haq}\\ \text{First}& 95& 55\\ \text{Second}& 104& 111\\ \text{Third}& 154& 126\\ \text{Fourth}& 23& 52\\ \text{Fifth}& 103& 109\end{array}$$

Who averages more in the ODI series and could probably get the man of the series award if the award is given to the person with highest average?

1. Inzamam-ul-haq

2. Can't say

3. Sachin Tendulkar

4. Both batsmen have the same average

Q. Question 16
If $\overline{x}$ is the mean of $x_1,x_2,\dots \dots x_n$, then for $a\ne 0$, the mean of $a{x}_1,a{x}_2,\dots \dots a{x}_n,\frac{x_1}{a},\frac{x_2}{a},\dots \dots \frac{x_n}{a}$ is:

A) $(a+\frac{1}{a})\overline{x}$
B) $(a+\frac{1}{a})\frac{\overline{x}}{2}$
C) $(a+\frac{1}{a})\frac{\overline{x}}{n}$
D) $\frac{(a+\frac{1}{a})\overline{x}}{2n}$

Q.

The mean of $7$ numbers is $25$. If one more number is included , the mean of the new set of numbers becomes $27$ . Find the included number.

Q. The numbers of pages of a book Rajesh read for the six consecutive days were 10, 15, 20, 8, 7, 12. Find the average number of pages he read every day.

1. 15
2. 12
3. 10
4. 11

Q. Find the average score of the following data.
10, 100, 1000, 10000, 100000

1. 22222
2. 2222
3. 222222
4. 222

Q. The marks scored by Rahul in five different subjects are 56, 85, 90, 76, 65. What is his average mark?

1. 85.4
2. 186
3. 74.4
4. 90

Q.

Runs scored by Ravi in his last seven innings are given below :

$68,74,82,100,20,18,58$

Find the mean of runs scored by Ravi in an inning.

Q.

The following are marks in a class assessment:

4, 6, 7, 5, 3, 5, 4, 5, 2, 6, 2, 5, 1, 9, 6, 5, 8, 4, 6, 7

Draw the Tally mark - frequency table and find the arithmetic mean.

Q. The average of $12$ numbers is $9$. If each number is multiplied by $2$ and added to $3$, the average of the new set of numbers is

1. $9$
2. $18$
3. $21$
4. $27$

Q. There are four children A, B, C and D. A has 6 chocolates, B has 7 chocolates, C has 8 chocolates and D has 10 chocolates. Which of these children has the average number of chocolates?

1. A
2. B
3. C
4. D

Q. The dot plot represents a random sample of 15 students studying science and economics as shown.

The measure of centre of science is and economics is .

1. 9 hours
2. 7 hours
3. 6 hours
4. 8 hours

Q. The average $50$ numbers is $30$. If two numbers, $35$ and $40$ are discarded, then the average of the remaining numbers is nearly:

1. $28.32$
2. $28.78$
3. $29.27$
4. $29.68$

Q.

The bar graph below shows the sales of newspapers (in millions) in six branches of a publishing company for the years 2013 and 2014.

i)What is the average sales of all the branches (in millions) for the year 2014?

ii) What is the total sales in the brances NP1, NP3 and NP5 for both years?