MEAN
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1) IF the height of 5 persons are 140,150,152,158,161cm find mean.
2) mean of 994,996,998,1002, 1000.
3) mean of first 7 natural numbers.
4) Find the mean of all factors
of 15.
5) mean of 10 prime numbers.
6) mean of X,x+3, x+5, x+7, x+9.
7) mean of first 5 multiple of 4.
8) mean of 3.4, 3.6, 4.2, 4.5, 5.1, 5.3, 6.2, 7, 8.2 , 9.3, 8.4.
9) The % of marks scored by students of a class in maths are: 64,36,48,62,90,63,71,48 find mean.
10) The Number of children in 10 families of a locality are: 2,4,3,2,0,3,5,1,1,1. Find mean.
11) The mean marks scored by100 students was found to be 40. Later on it was discovered that a score 52 was misread as 82. Find the correct mean.
12) The traffic police recorded the speed(in km/hr) of 10 motorists as 47,53,60,39,42,55,57,52,48,63. Later on an error in recording instrument was found. Find the correct Average speed of the motorists if the instrument recorded 5 km/hr less in each case.
13) The mean of five Numbers is 30. If one of the number is excluded, their mean is 25. Find the excluded Number.
14) The mean weight per student in a group of 7 students is 60 kg. The individual weight of 6 of them are 52,54,55,53,56,54. Find the weight of the seventh student.
15) The mean weight of 8 students is 16. If each Number is multiplied by 2, what will be the new mean.
16) the mean of 5 Number is 18. If one number is excluded, their mean is 16. Find the excluded Number.
17) The mean of 200 items was 50. Later on, it was discovered that the two items were misread as 92 and 7 instead of 192 and 77. Find the correct mean.
18) Find the mean of first 8 odd natural numbers.
19) The mean of 11 Numbers is 35. If the mean of first 6 Number is 32 and that of last 6 Number is 37, find the sixth Number.
20) There are 40 Numbers in a group. If the mean of first 10 is 4.5 and that of the remaining 30, is 3.5, find the mean of the whole group.
21) A group of 10 items has mean 6. If the mean of 4 of these items is 7.5, find the mean of the remaining items.
22) The A. M of a set of 50 Numbers is 38. If two numbers of the set namely 55 and 45 are discarded, find the AM of the remaining set of numbers.
23) Find arithmetic mean of a, a+d, a+2d, a+3d, a+ 4d,
24) Following is the data of the heights of a group of students: 61,62,63,64,60,65,63,64,64,66,64. Now suppose that a group of students whose heights are 60,96, 59,68,67, and 70 inches is added to the original group.
a) What is the mean of the new combined group ?
b) What is the difference between the mean of the original group and the mean of the combined group so formed by addition of new students to the group ?
25) The mean age of a group of 100 persons was found to be 32.02. Later, it was found that age 57 was misread as 27. Then the correct mean ?
26) The A. M of 8,1,6.
27) The arithmetic mean of 8,1,6 with weights 3,2,5 is.
28) If 7,4,9 be the A. M of three separate groups containing 6,2,5 observations respectively, then the A. M of all the 13 observations is:
29) The algebric sum of deviations of 8,1,6 from their A. M is-
30)a) Rani bought Rs6 worth of range from five markets at 15,20,25,30,50 paise per orange. Find Average price
b) What would be the average price, if she purchased 20 oranges from each market ?
31) The weighted mean of the four numbers 26,128,12, and 4 is 10.4. If the weight of the first three Numbers are are 1,3 and 4. Find the 4th no.
32) Find the A. M of 3,5,7,9….47 ?
33) If a variable assumes the value 1,2,3,...10 with frequencies 1,2,3,...10 find its mean
34) The weighted A. M of 3,5 and 10 with x,y,z is known to be 8. What is the weighted AM if the weights are changed to 2x,2y,2z.
35) A variable x takes the value 10 and 20 with equal frequencies. Find the A. M.
36) A variable x takes all integral value from 1 to 10 with equal frequencies. Find its AM.
37) If the AM of 3,5,x,12,17 be 9, find the value of x.
38) The AM of -2,3,0,5,4 is -
39) The AM of a variable y is 10. Find the mean of the variable 5y-10.
40) The weekly wages of 5 labourers are 40,60,36,45,25. Find AM.
41) Find the AM of 14,16,19,25,21.
42) Find AM of 24,72,108,144.
43)The A. M of 5,8,9,14,-16
44) The A. M of 3,4,5,6,7,8,9,10.
45) If A. M of 25, 27, 31, 35, 39, x
is 38 then find x.
45) The Numbers 3.2,5.8,7.9 and 4.5 have frequencies x,x+2, x-3 and x+6. If Arithmetic mean is 4.876. find x.
46) A sample of size 50 has mean 54.4 and another sample of size 100 has mean 50.3. if the two samples are pooled together, find the mean of the combined sample.
47) The mean of 20 observations is 85; but it was later found that two of the observations were wrongly read as 75 and 70 instead of 57 and 60. Find the actual mean.
48) The weighted Arithmetic mean of first n natural Numbers whose weights are equal to the corresponding Numbers is equal to:
a)(2n-1)/3. b) (2n-1)/6
c) (2n+1)/3. d) none
49) The mean wage of 100 workers working in a factory running two shifts of 60 and 40 workers is 38.
The mean wage of 60 laborers working in the morning shift is Rs40.
Find the mean-wage of labourers working in the evening shift.
50) The mean of 20 observations is 16.5. If by mistake one observation was copied 12 instead of 21. Find the correct mean.
51) The mean salary of 77 workers in a company was Rs78. The mean salary of 32 of them was Rs75 and other 25 had a mean salary of Rs82. What was the mean salary of the remaining.
52) The mean salary to all workers was Rs5000. The mean salary paid to male and female workers was Rs5200 and Rs4200. Determine the% of males and females workers by the company.
53) The mean of marks scored by 30 girls of a class is 44%. The mean marks of 50 boys is 42%. Find the mean for the whole class.
54) A set of 20 values have mean
54. Another set of values have
mean 60. If the combined mean
is 56, how many values are
there in the letter set ?
55) Harmonic mean of 1,8,6 is :
56) The AM of two observations is
36 and their GM is 24, find HM.
57) Find GM of 3,-2,4,0,5.
58) The HM of -3,2,4,0,-5 is
59) The G. M of 2,6,18,54,162.
60) G. M of 8,12,18,27.
61) H. M of 4,8,12,16,20.
62) Find HM and GM of 1,9,81.
63) AM=25; HM=9 then GM =?
64) Find GM of 2,9,12.
65) Find GM of 6,24,12.
66) Find HM of 3,6,24,48.
67) Find GM of 4,6,12,72
68) The G. M of 10,30,90.
69) The G. M of 24,20,15,45,75.
70) H. M of 1,2,3,4,5.
71) H. M of 1/1,⅓,1/9,1/27.
72) HM of 1,½,⅓,.....1/n is ?
73) The harmonic mean of
½,¼,⅙,⅛
74) A,G,H are the A. M, G. M and the H. M of any two positive numbers, then the H. M of number is
a)A≥G≥H. b) A≥G and G≤H
c) G≥H≥A. d) G≥A ≥H
75) If the A. M and G. M of two positive numbers are 12 and 6 then find H. M.
76) The G. M, H. M and A. M of three observations being 3.63, 3.27, and 4 respectively. Find the observations.
77) The A. M of 1,3,5,.....29 is-
78) The A. M of a variable x is 40. Find the mean of y, when y=4x-10
79) The mean age of a group of 30 girls is 20 years, and that of a group of 20 boys is 30 years. If the two groups are taken together to form a new group, what is the mean age of this group!
80) The mean marks of 170 students in a certain class is 75. The mean mark of boys in the class is 85, and of the girls is 65. Find the number of boys and girls in the class.
81) The mean marks in an examination by two groups of students were found to be 75,85. What will be the ratio of students in the two groups, if the average marks for all students was 100.
82) For a set of 10 observations, what will be the mean for the values of x: 10,10,10. .,10
83) The A. M of 7 items is 10. If one more item is added to the series. Then the A. M becomes 12. Find the value of the 8tg item.
84) What will be the A. M of 1st natural numbers ?
85) What will be the weighted AM of the first n square of natural numbers when the numbers weighted by the corresponding Numbers.
86) The AM of a set of values is 15. If 5 is added to each value, the new A. M is-
87) The A. M of a set of values is 30. If 5 is substracted to each term, the new AM is-
88) The AM of a set of values is 25. If 5 is multiplied to each term. The new AM is-
89) The AM of a set of values is 30 . If 5 is divided by each term. The new AM is-
90)The AM of 1,2,2²,.......2^9 is-
91)The G. M 50 Numbers is 38.032. The G.M of 14 of them is 70, what is the GM of other members?
92) The GM of 14 observations is 70, and the GM of 36 others is 30. What will be the GM of all the observations taken together?
93) A train ran at x km/hr from A to B, and returned from B to A at y km/hr. The average speed is-
94) A train ran 12 km at 4km/hr, and then 10 km at 5 km/hr. The average speed is-
95) The weighted H.M of first 11 natural numbers weights are equal to the corresponding Numbers, is-
96) If the interest rate paid on each 5 Different sums of money yielding 2%,3%,4%,5% and 6% simple interest p.a. respectively be the same, what is the average yield% on the total sum invested ?
97) If 5y=22x be the Relation between the variables x and y and GM of x=10, then GM of y is-
98) X: 2 3 4 5 7 find mean
F: 6 8 12 10 4
99) Find the mean of:
C.I:40-44 45-49 50-54 55-59 60-64
F: 17 25 30 20 8
100) If mean is 3.7857 find a and b
X: 0 1 2 3 4 5 6 7. Total
F: 3 5 a 7 b 9 12 6 70
101) X: 0.5 1.5 2.5 3.5 4.5 7.5 12.5
. F: 16 69 89 74 74 213 70
Find A. M
102) If mean is 64.45 find a.
X: 60-62 63-65 66-68 69-71 72-74
F: 15 54 a 83 24
103) If mean is 11.09 total frequencies is 100 find a, b
C. I: Frequency
09.3-09.7 2
09.8-10.2 5
10.3-10.7 a
10.8-11.2 b
11.3-11.7 14
11.8-12.2 6
12.3-12.7 3
12.8-13.2 1
104) For the two frequency distribution given below the mean from 1st was 31.80 and from the 2nd was 34.17 find a , b.
X: 10-20 20-30 30-40 40-50 50-60
1st : 5 5 10 a b
2nd: 2 8 6 2a b
105) A firm buys Rs10000 of plants and equipment in January 1980 arranges the cost and depreciation according to the following:
Category:. A B C
COST: 6000 3000 1000
DEPRECIATION: 6% 3% 1%
FIND the average depriciation rates for 1980.
106) Find H. M of following:
X: 1 2 3 4 5
F: 10 20 40 6 4
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