Question : Find the average of odd numbers from 15 to 1065
Correct Answer 540
Solution & Explanation
Solution
Method (1) to find the average of the odd numbers from 15 to 1065
Shortcut Trick to find the average of the given continuous odd numbers
The odd numbers from 15 to 1065 are
15, 17, 19, . . . . 1065
After observing the above list of the odd numbers from 15 to 1065 we find that the difference between two consecutive terms are equal. This means the list of the odd numbers from 15 to 1065 form an Arithmetic Series.
In the Arithmetic Series of the odd numbers from 15 to 1065
The First Term (a) = 15
The Common Difference (d) = 2
And the last term (ℓ) = 1065
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 15 to 1065
= 15 + 1065/2
= 1080/2 = 540
Thus, the average of the odd numbers from 15 to 1065 = 540 Answer
Method (2) to find the average of the odd numbers from 15 to 1065
Finding the average of given continuous odd numbers after finding their sum
The odd numbers from 15 to 1065 are
15, 17, 19, . . . . 1065
The odd numbers from 15 to 1065 form an Arithmetic Series in which
The First Term (a) = 15
The Common Difference (d) = 2
And the last term (ℓ) = 1065
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 15 to 1065
1065 = 15 + (n – 1) × 2
⇒ 1065 = 15 + 2 n – 2
⇒ 1065 = 15 – 2 + 2 n
⇒ 1065 = 13 + 2 n
After transposing 13 to LHS
⇒ 1065 – 13 = 2 n
⇒ 1052 = 2 n
After rearranging the above expression
⇒ 2 n = 1052
After transposing 2 to RHS
⇒ n = 1052/2
⇒ n = 526
Thus, the number of terms of odd numbers from 15 to 1065 = 526
This means 1065 is the 526th term.
Finding the sum of the given odd numbers from 15 to 1065
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 15 to 1065
= 526/2 (15 + 1065)
= 526/2 × 1080
= 526 × 1080/2
= 568080/2 = 284040
Thus, the sum of all terms of the given odd numbers from 15 to 1065 = 284040
And, the total number of terms = 526
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 15 to 1065
= 284040/526 = 540
Thus, the average of the given odd numbers from 15 to 1065 = 540 Answer
Similar Questions
(1) Find the average of the first 1448 odd numbers.
(2) Find the average of odd numbers from 11 to 991
(3) Find the average of the first 1294 odd numbers.
(4) Find the average of the first 4370 even numbers.
(5) What is the average of the first 1719 even numbers?
(6) Find the average of odd numbers from 13 to 563
(7) Find the average of the first 976 odd numbers.
(8) Find the average of even numbers from 10 to 1850
(9) Find the average of the first 227 odd numbers.
(10) Find the average of odd numbers from 11 to 961