Question:
Find the average of odd numbers from 11 to 1039
Correct Answer
525
Solution And Explanation
Solution
Method (1) to find the average of the odd numbers from 11 to 1039
Shortcut Trick to find the average of the given continuous odd numbers
The odd numbers from 11 to 1039 are
11, 13, 15, . . . . 1039
After observing the above list of the odd numbers from 11 to 1039 we find that the difference between two consecutive terms are equal. This means the list of the odd numbers from 11 to 1039 form an Arithmetic Series.
In the Arithmetic Series of the odd numbers from 11 to 1039
The First Term (a) = 11
The Common Difference (d) = 2
And the last term (ℓ) = 1039
The average of the numbers forming an Arithmetic Series
= The first term (a) + The last term (ℓ)/2
⇒ The average of numbers forming an Arithmetic Series = a + ℓ/2
Thus, the average of the odd numbers from 11 to 1039
= 11 + 1039/2
= 1050/2 = 525
Thus, the average of the odd numbers from 11 to 1039 = 525 Answer
Method (2) to find the average of the odd numbers from 11 to 1039
Finding the average of given continuous odd numbers after finding their sum
The odd numbers from 11 to 1039 are
11, 13, 15, . . . . 1039
The odd numbers from 11 to 1039 form an Arithmetic Series in which
The First Term (a) = 11
The Common Difference (d) = 2
And the last term (ℓ) = 1039
The Average of the given numbers
= Sum of the given numbers/Total number of given numbers
Thus, to find the average of the given numbers, first, we need to find their sum and the total number of given numbers
Finding the number of terms
For an Arithmetic Series, the nth term
an = a + (n – 1) d
Where
a = First term
d = Common difference
n = number of terms
an = nth term
Thus, for the given series of the odd numbers from 11 to 1039
1039 = 11 + (n – 1) × 2
⇒ 1039 = 11 + 2 n – 2
⇒ 1039 = 11 – 2 + 2 n
⇒ 1039 = 9 + 2 n
After transposing 9 to LHS
⇒ 1039 – 9 = 2 n
⇒ 1030 = 2 n
After rearranging the above expression
⇒ 2 n = 1030
After transposing 2 to RHS
⇒ n = 1030/2
⇒ n = 515
Thus, the number of terms of odd numbers from 11 to 1039 = 515
This means 1039 is the 515th term.
Finding the sum of the given odd numbers from 11 to 1039
The sum of all terms (S) in an Arithmetic Series
= n/2 (a + ℓ)
Where, n = number of terms
a = First term
And, ℓ = Last term
Thus, the sum of all terms (S) of the given odd numbers from 11 to 1039
= 515/2 (11 + 1039)
= 515/2 × 1050
= 515 × 1050/2
= 540750/2 = 270375
Thus, the sum of all terms of the given odd numbers from 11 to 1039 = 270375
And, the total number of terms = 515
Since, the average of the given numbers
= Sum of the given numbers/Total number of given numbers
Thus, the average of the given odd numbers from 11 to 1039
= 270375/515 = 525
Thus, the average of the given odd numbers from 11 to 1039 = 525 Answer
Similar Questions
(1) Find the average of even numbers from 8 to 456
(2) Find the average of the first 2228 even numbers.
(3) Find the average of odd numbers from 9 to 785
(4) Find the average of odd numbers from 3 to 195
(5) Find the average of even numbers from 6 to 1030
(6) Find the average of odd numbers from 9 to 215
(7) Find the average of the first 3453 odd numbers.
(8) Find the average of even numbers from 10 to 1934
(9) Find the average of even numbers from 6 to 1558
(10) Find the average of the first 1437 odd numbers.