MEAN
1) Find the mean of first 7 even natural numbers. 8
2) The number of children in 25 families of a locality are recorded as follows: 3,1,4,0, 2,2, 1,1, 2, 3, 3, 2, 2, 2, 5, 0, 1, 4, 1, 2, 1, 2, 3, 0, 1, 4. Find the mean number of children per family. 2.
3) The marks obtained by by 10 students in a test are 56, 54, 71, 60, 62, 72, 59, 64, 70, 52. Find
A) the mean marks of the student
B) The mean marks of the student if 5 extra marks are given to each student. 62, 67
4) A student obtained 60, 75 and 85 marks, respectively in three monthly examination in Physics and 95 marks in the final examination. The three monthly examination are of equal weightage whereas the final examination is waghted twice as much as a monthly examination. Find his mean marks for Physics. 82
5) Find the mean of
A) first five natural natural numbers.
B) first five positive odd integers
C) first five multiples of 3 multiples of 3.
E) all factors of 10. 3,5,6,9,4.5
6) find the mean of the numbers 96, 98, 100, 102, 104. 100
7) find the mean of the numbers 994, 996, 998, 1000, 1002. 998
8) find the mean of x, x+2, x+4, x+6, and x+8. x+4
9) If the mean of 6, 8, 5, 7, x and 4 is 7, find the value of x. 12
10) Following are the weight(in kg) of 10 newly born babies in a hospital on a particular day: 3.4, 3.6, 4.5, 3.9, 4.1, 3.8, 4.5, 4.4, 3.6. Find the mean. 5.6
11) The traffic police recorded the speed(in km/hr) of 10 motorists as 47, 53, 49, 60, 39, 42, 55, 57, 52, 48. Later an error in the recording instruments was found. Find the correct average speed of the motorists if the instrument recorded the speed 5 km/hr less in each each case. 45.2
12) If the mean of 6, 4, 7, p and 10 is 8, find the value of p. 13
13) If the mean of 5 numbers is 7, find the mean of another 5 numbers numbers which are obtained by adding 2 to each case of the 5 numbers. 9
14) Find the sum of the deviations of the variate values 2, 4, 6, 8, 14 from their mean. 0
15) The mean of 8 numbers is 15. If each number is multiplied by 2, what will be the new mean. 30
16) The mean is 21 numbers is 15. If each number is multiplied by 2, what will be the new mean. 30
17) There are 45 students In a class, of which 15 are girls. The average weight of 15 girls is 45 kg and that of 30 boys is 52kg. Find the mean weight in kg of the entire class. 49.67
18) A school has 4 sections in Class X having 40, 35, 45 and 42 students. The mean marks obtained in a Chemistry Test are 50, 60, 55, and 45 respectively, for the 4 sections. Determine the overall average of marks per students. 52.2
19) mean of 25 observations was found to be 78.4. but later on it was discovered that 96 was misread as 69. Find the correct mean. 79.48
20) Mean of 40 observations was 160. It was detected on rechecking that the value 165 was wrongly occupied as 125 for computation of a mean. Find the correct mean. 16.1
21) The mean weight per student in a group of seven students is 55 kg. The individual weight(in kg) of 6 of them are 52, 58, 55, 53, 56, and 54. Find the weight of the 7th student. 57 kg
22) The mean weight of 150 students in a certain class is 60 kg. The mean weight of boys in the class of 70 kg and that of the girls is 55kg. Find the number of boys and the number of girls in the class. 50, 100
23) In a class, the average score of girls in an examination in 73 and that of a boy is 71. The average score for the whole class 71.8. Find the percentage of girls and the boys in the boys in the class. 40, 60%
24) A train travels between two stations A and B, while going from A to B, its average speed is 100 km/hr, and when coming back from B to A, its average speed is 150 km/hr. Find the average speed during the whole journey. 120
25) The mean height of 10 students is 153 centimetre. it is discovered later on that while calculating the mean the reading 151cm was wrongly read as as 141cm. Find the correctly mean. 154
26) The mean of five number is 27. If one number is excluded, their mean is it 25. Find the excluded number. 35
27) There are 50 students In a class of which 40 are and the rest girls. The average weight of the the class is 44 kg and the average weight of the girls is 40 kg. Find the average weight of the the boys. 45
28) There are 120 boys in a class in which twenty of them are girls and the rest boys. If the average marks in Maths of the boys is 65% and that of the girl is 80%. Find the average mark of the class. 56.83
29) The average score of boys in an examination of a school is 71 and that of girls is 73. The average of the school in that examination in 71.8. Find the ratio of the number of boys to the number of girls appeared in the examination. 3:2
30) The mean of marks secured by 25 students of of section A of class 47, that of 35 students of section B is 51 and that of 30 students of Section C is 53 students of Section C is 53 . Find the mean of the marks of students of three sections of class sections of class X. 50.55
31) The average monthly wage of a group of 10 persons is Rs.1500. One member of the group whose monthly wage is Rs1350, left the group and is replaced by a new member whose monthly wage is Rs.1200. Find the new monthly wage. 1485
32) The mean of monthly salary of 10 members of a group is Rs1445. One more member whose monthly salary is Rs1500 has joined the group. Find the mean of monthly salary of 11 members of the group. 1450
33) The mean of marks secured by hundred students was found to be 40. later on it was discovered that score of 53 was misread 83. Find the correct mean. 39.7
34) The aggregate monthly expenditure of a family was Rs 4050 during the first three months. Rs 4260 during the next four months and Rs4326 during the last five months of a year. If the total saving during the year be Rs 6120, find the average average monthly income. 4678
35) the average of 11 results is 50. If the average of the first six results is 49 and that of last is 52, find the sixth sixth result. 56
36) A batsman in his 12th innings makes a score 63 runs and thereby increases his average score by 2. What is his average after the 12th innings. 41.
37) The average age of 8 persons in a committee is increased by 2 years, when 2 men aged 35 years and 45 years are substituted by two women. Find the average age of these women. 48
38) A Car owner buys petrol at Rs 17, Rs19 and Rs 20 per litre for 3 consecutive years. compute the average cost pee litre, If he spends Rs 6460 per year. 18.58
39) The arithmatic mean of 3, 7, 5, x, 8, -3, is 4. Find x. 4
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