According to the basic formula of average,
Average(A)= Sum (S) / Number(N)
? 38 = S/50
? S = 38 x 50 = 1900
Sum of remaining number after eliminating 45 and 55
= 1900 - (45 + 55) = 1800
Average of remaining numbers = (Sum of remaining number) / (Remaining number)
= 1800 / ( 50 - 2)
= 1800/48
= 37.5
Mean = (sum of observation) / (number of observation)
Sum of observation is given as = 70
Number of observation = 20
? Mean = 70/20 = 3.5
But, here observation starts from= 23.
? Mean = 23 + 3.5 = 26.5
Total distance = (200 + 300 + 500) = 1000
Total time = 200/40 + 300/20 + 500/10 = 5 + 15 + 50 = 70 hr
Average speed = Total distance / Total time =1000 / 70 = 14.2857 Km/hr.
Let the height of A , B, C be y cm, y cm and (y - 2) cm respectively
Then, y + y + (y - 2) = 163 x 40 - 162 x 37
? 3y - 2 = 526
? y = 176 cm
Total present age of the family = 6 x 22
= 132 years
Total age of the family 7 years ago = 132 - 7 x 6
= 90 years
At that time, the number of members was 5
? Average age at time = 90 / 5 years
= 18 years
From question
A + B + C = 3 x 84 = 252 ....(i)
A + B + C + D = 4 x 80 = 320 ...(ii)
From eq. (ii) - (i)
D = ( 320 - 252 ) = 68
From question E = D + 3
? E =( 68 + 3 ) = 71
Now , B + C + D + E = 4 x 79 = 316
? B + C + D = 316 ? 71 = 245
So , A = 320 - 245 = 75 kg .
Total number of all students of the class = 30 x 45 = 1350
? New average after adjustment = (1350 - 45 + 15)/30 = 1320/30 = 44
Sum of marks of 7 students = Mean x Number of students
= 226 x 7 = 1582
Now, total marks of 6 students = (340 + 180 + 260 + 56 + 275 + 307) = 1418
? Marks obtained by seventh students
= Total marks of seven students - Total marks of the six student
= 1582 - 1418
= 164
Total age of 4 member = 25 x 4 = 100 yr
Total age of 5 members including the head
= 5 x (25 + 25 x 20/100)
= 5 x 30 = 150 yr
? Age of the head = 150 - 100 = 50 yr
Total age of 3 woman = 2 X 11 + (32 + 33 + 34)
= 22 + 99 = 121 yr.
? Average age of 3 woman = 121/3 = 401/3 yr
Total weight of 2 men
= 1 x 10 + (42 + 38) = 10 + 80 = 90 kg
? Average weight of 2 men = 90/2 = 45 kg
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