Given data:
Average of eight consecutive odd numbers = 28.
Formula used:
Average of eight consecutive odd numbers = 8sum
Sum of largest and smallest odd number = Largest odd number + Smallest odd number
Calculation:
Let us assume the first odd number as (n - 7).
Other consecutive odd numbers would be (n - 5), (n - 3), (n - 1), (n + 1), (n + 3), (n + 5), and (n + 7).
Sum = (n - 5) + (n - 3) + (n -1) + (n + 1) + (n + 3) + (n + 5) + (n + 7) = 8n
Average of eight consecutive odd numbers = 88n
Hence, 88n= 28 or n = 28.
⇒ Largest odd number = n + 7 = 28 + 7 = 35
⇒ Smallest odd number = n - 7 = 28 - 7 = 21
Sum of largest and smallest odd number = 35 + 21 = 56
The sum of the largest and smallest odd numbers is 56.
Shortcut TrickGiven:
The average of 8 consecutive odd numbers is 28
Concept Used
1, 3, 5, and 7 are four consecutive odd numbers.
Average of above numbers is ,
⇒ (1 + 3 + 5 + 7)/4 = 4
Also, 4 is the middle number of the given series
Hence in such cases the average is middle number of the series.
Calculation:
Here, from the concept used we know that,
28 is the middle term of 8 consecutive numbers series
Hence we can say that,
There are 4 consecutive odd numbers before 28 &
There are 4 consecutive odd numbers after 28
So the series of 8 numbers is,
⇒ 21, 23, 25, 27, 28, 29, 31, 33, 35
The sum of the smallest and largest numbers is,
⇒ 21 + 35 = 56
The sum of the largest and smallest odd numbers is 56.