Question 1 :
In a coconut grove$ (x + 2)$ trees yield $60$ nuts per year, $x$ trees yield $120$ nuts per year and  $(x - 2)$  trees yield $180$ nuts per year.If the average yield per year per tree be $100$ then find x.
Question 2 :
The average of 11, 12, 13, 14, and x is 13. The value of x is 
Question 3 :
A student obtained the following marks percentage in an examination:<br/>English - $50$, Accounts - $75$, Economics - $60$, B.Std. -$80$, Hindi - $55$.<br/>If weights are $2, 3, 3, 2, 1$ respectively allotted to the subjects, his weighted mean is
Question 4 :
The arithmetic mean of $n$ numbers is $x$. If the sum of the first $(n - 1)$ numbers is $k$, then the $n$th number is?<br/>
Question 5 :
The average of three numbers is 60. The first is 1/4th of the sum of the other two. The first number is 
Question 6 :
In a family, there are $8$ men, $7$ women and $5$ children whose mean ages separately are respectively $24,20$ and $6$ years. The mean age of the family is
Question 7 :
The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is:
Question 9 :
The mean of $100$ observations is $50$. If one of the observations which was $50$ is replaced by$ 150$, the resulting mean will be :<br/>
Question 11 :
A man spends equal amount on purchasing three kind of pens at the rate Rs. $5$ per pen, Rs. $10$ per pen and Rs. $20$ per pen. The average cost of one pen is
Question 12 :
The heights (in $cm$) of $8$ girls of a class are $140, 142, 135, 133, 137, 150, 148$ and $138$ respectively. Find the mean height of these girls.<br/>
Question 13 :
The average (arithmetic mean) of $t$ and $y$ is $15$, and the average of $w$ and $x$ is $15$. What is the average of $t, w, x$ and $y$? 
Question 15 :
The average of four consecutive even numbers is $15$. The $2$nd highest number is
Question 16 :
The mean of the data set comprising go 16 obser vations is 16.If one of and three new observations valued 3,4 and 5 are added to the data, then
Question 17 :
The average weight of $10$ men is decreased by $ 3 \space kg$  when one of them whose weight is $80 kg $  is replaced by a new person. The weight of the new person is<br/>
Question 18 :
Find the mean of the observations $425, 430, 435, 440, 445, ........... 495.$
Question 19 :
The arithinetic mean of $5, 6, 8, 9, 12, 13, 17$ is<br/>
Question 20 :
The weighted arithmetic mean ofthe first $n$ natural numbers whose weights are equal to the corresponding numbers is given by,
Question 21 :
M=$\left \{1, 2, 3, 4, 5, 6, 7\right \}$<br/>Each number in set $N$ is generated by dividing each number in set $M$ by $2$. Calculate the arithmetic mean of numbers in $N$.<br/>
Question 22 :
The average (arithmetic mean) of a particular set of seven numbers is $12$. When one of the numbers is replaced by the number $6$, the average of the set increases to $15$. What is the number that was replaced?
Question 23 :
The mean of $13$ observations is $14$. If the mean of the first $7$ observations is $12$ and that of the last $7$ observations is $16$, then the $7^{th}$ observation is ___________.
Question 24 :
The average of the four even numbers between $31$ and $39$ is<br/>
Question 25 :
A student got marks in $5$ subjects in a monthly test is given below<br/>$2, 3, 4, 5, 6$<br/>in these obtained marks, $4$ is the
Question 26 :
The average of $100$ numbers is $44$. The average of these $100$ numbers and four other numbers is $50$. What is the average of the four new numbers?
Question 28 :
The mean of $20$ observations is $12.5$ by error one observation was noted $-15$ instead then the correct mean is
Question 29 :
The mean of $100$ items was found to be $30$. If two observation were wrongly taken as $32$ and $12$ instead of $23$ and $11$, find the correct mean.
Question 30 :
If $6$, $p$, $12$,  $8$ and  $9$ mean of the data is $9$ then $p=$ ?<br/>
Question 31 :
The mean of the squares of the  first n natural numbers is?<br/>
Question 32 :
The data $11, 6, 22, 7, 10, 6, 15$  is the times in minutes it takes seven students to go to school from their homes Which statement about the data is false? 
Question 33 :
The average maximum temperature for 7 days from the 12th September to 18th September is$35^\circ C$and that for 7 days from 13th to 19thSeptember is $34^\circ C$. From this we can conclude that
Question 34 :
A group of $10$ items has arithmetic mean $6$. If the arithmetic mean of $4$ of these items is $7.5$, then the mean of the remaining items is
Question 35 :
Rahul's mean score in $5$ tests was $84$. His mean score in the first $4$ of these tests was $87$. Calculate his score in the fifth test.
Question 36 :
The average (arithmetic mean) of all the grades on a certain algebra test was $90$. If the average of the $8$ males grades was $87$, and the average of the females grades was $92$, calculate the number of female students.
Question 37 :
Average of $8$ numbers is $20$, that of the first two is $15.5$ and that of the next three is $21\dfrac {1}{3}$, the $6^{th}$ is less than the $7^{th}$ by $4$ and $7$ less than the $8^{th}$. The last number is:
Question 38 :
There are $50$ numbers. Each number is subtracted from $53$ and the mean of the numbers so obtained is found to be $3.5$. The mean of the given numbers is:<br/>
Question 39 :
The ages of $5$ children are $13, 15, 11, 9$ and $8$ years respectively. The average age is<br/>
Question 40 :
A contractor employed $18$  labourers at Rs. $12$ per day, $ 10$ labourers at Rs.$ 13.50 $ per  day,$ 5$ labourers at Rs.$ 25 $ per  day and $2$ labourers at Rs.$ 42$ per day. The average  wage of a labourer per day is  <br/>
Question 41 :
If the range of $14, 12, 17, 18, 16, x$ is $20$ and $x>0$, the value of $x$ is<br>
Question 42 :
A firm of readymade garments make both men's and women's shirt. Its profit average is $6$% of sales. Its profits in men's shirt average $8$% of sales and women's shirts comprise $60$% of output. The average profit per sales rupee in women's shirts is :
Question 44 :
The mean of the median ,the mode,and the range of the following data are:<br/>$84,56,39,45,54,39,56,54,84,21,77,56$ 
Question 45 : The mean of following distribution is $6.5$. Find the value of $k$.<br/><table class="table table-bordered"><tbody><tr><td> $x$</td><td>$2$ </td><td>$4$ </td><td>$6$ </td><td>$8$ </td><td>$10$ </td></tr><tr><td>$f$ </td><td>$5$ </td><td>$3$ </td><td>$7$ </td><td>$6$ </td><td>$k$ </td></tr></tbody></table>
Question 46 :
What is the average (arithmetic mean) of all numbers multiples of $6$ from $6$ to $510$ inclusive?
Question 50 : Find the mean of the following continuous distribution.<br/><table class="table table-bordered"><tbody><tr><td> Class interval</td><td>$10-15$ </td><td>$15-20$ </td><td>$20-25$ </td><td>$25-30$ </td><td>$30-35$ </td></tr><tr><td> Frequency</td><td> $8$</td><td>$11$ </td><td>$6$ </td><td>$13$ </td><td>$12$ </td></tr></tbody></table>
