Question:
Find the average of odd numbers from 3 to 755
Correct Answer
379
Solution And Explanation
Solution
Method (1) to find the average of the odd numbers from 3 to 755
Shortcut Trick to find the average of the given continuous odd numbers
The odd numbers from 3 to 755 are
3, 5, 7, . . . . 755
After observing the above list of the odd numbers from 3 to 755 we find that the difference between two consecutive terms are equal. This means the list of the odd numbers from 3 to 755 form an Arithmetic Series.
In the Arithmetic Series of the odd numbers from 3 to 755
The First Term (a) = 3
The Common Difference (d) = 2
And the last term (ℓ) = 755
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 3 to 755
= 3 + 755/2
= 758/2 = 379
Thus, the average of the odd numbers from 3 to 755 = 379 Answer
Method (2) to find the average of the odd numbers from 3 to 755
Finding the average of given continuous odd numbers after finding their sum
The odd numbers from 3 to 755 are
3, 5, 7, . . . . 755
The odd numbers from 3 to 755 form an Arithmetic Series in which
The First Term (a) = 3
The Common Difference (d) = 2
And the last term (ℓ) = 755
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 3 to 755
755 = 3 + (n – 1) × 2
⇒ 755 = 3 + 2 n – 2
⇒ 755 = 3 – 2 + 2 n
⇒ 755 = 1 + 2 n
After transposing 1 to LHS
⇒ 755 – 1 = 2 n
⇒ 754 = 2 n
After rearranging the above expression
⇒ 2 n = 754
After transposing 2 to RHS
⇒ n = 754/2
⇒ n = 377
Thus, the number of terms of odd numbers from 3 to 755 = 377
This means 755 is the 377th term.
Finding the sum of the given odd numbers from 3 to 755
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 3 to 755
= 377/2 (3 + 755)
= 377/2 × 758
= 377 × 758/2
= 285766/2 = 142883
Thus, the sum of all terms of the given odd numbers from 3 to 755 = 142883
And, the total number of terms = 377
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 3 to 755
= 142883/377 = 379
Thus, the average of the given odd numbers from 3 to 755 = 379 Answer
Similar Questions
(1) Find the average of the first 3516 odd numbers.
(2) Find the average of odd numbers from 7 to 509
(3) Find the average of the first 2190 odd numbers.
(4) Find the average of even numbers from 4 to 1762
(5) What is the average of the first 718 even numbers?
(6) Find the average of even numbers from 4 to 258
(7) What is the average of the first 683 even numbers?
(8) Find the average of even numbers from 10 to 1856
(9) Find the average of the first 1921 odd numbers.
(10) Find the average of odd numbers from 15 to 583