There are 7 consecutive integers. The average of first 5 is A. The average of all 7 integers will be?
Answers
Let the first term be x, and the succeding terms x+1,x+2,.....x+6
Now,
[x+(x+1)+(x+2)+(x+3)+(x+4)]/5=A
(5x+10)/5=A
x+2=A
x=A-2 ⇒(i)
So,
Average of all 7 integers,
=[5x+10 +(x+5)+(x+6)]/7
=(7x+21)/7
=x+3
=A-2+3
=A+1 [from (i)]
Answer:
I hope it will help u
1, 2, 3, 4, 5, 6, 7
Here number of values are 7, and difference between two consecutive values is equal, therefore average of this series is middle number = (1+ total terms)th/2 = 4th term = 4
Proof: average = sum of numbers/ total number of values
= (1+2+3+4+5+6+7)/7 = 28/7 = 4
In similar way we have average of first 7 integers of an odd number series is 37
Average of 7 terms is 4th term = 37
and average of 13 terms = (1+13)/2 = 7th term
4th term = 37
5th = 39
6th = 41
7th = 43 (Ans)
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