Question : Find the average of even numbers from 4 to 708
Correct Answer 356
Solution & Explanation
Solution
Method (1) to find the average of the even numbers from 4 to 708
Shortcut Trick to find the average of the given continuous even numbers
The even numbers from 4 to 708 are
4, 6, 8, . . . . 708
After observing the above list of the even numbers from 4 to 708 we find that the difference between two consecutive terms are equal. This means the list of the even numbers from 4 to 708 form an Arithmetic Series.
In the Arithmetic Series of the even numbers from 4 to 708
The First Term (a) = 4
The Common Difference (d) = 2
And the last term (ℓ) = 708
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 even numbers from 4 to 708
= 4 + 708/2
= 712/2 = 356
Thus, the average of the even numbers from 4 to 708 = 356 Answer
Method (2) to find the average of the even numbers from 4 to 708
Finding the average of given continuous even numbers after finding their sum
The even numbers from 4 to 708 are
4, 6, 8, . . . . 708
The even numbers from 4 to 708 form an Arithmetic Series in which
The First Term (a) = 4
The Common Difference (d) = 2
And the last term (ℓ) = 708
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 even numbers from 4 to 708
708 = 4 + (n – 1) × 2
⇒ 708 = 4 + 2 n – 2
⇒ 708 = 4 – 2 + 2 n
⇒ 708 = 2 + 2 n
After transposing 2 to LHS
⇒ 708 – 2 = 2 n
⇒ 706 = 2 n
After rearranging the above expression
⇒ 2 n = 706
After transposing 2 to RHS
⇒ n = 706/2
⇒ n = 353
Thus, the number of terms of even numbers from 4 to 708 = 353
This means 708 is the 353th term.
Finding the sum of the given even numbers from 4 to 708
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 even numbers from 4 to 708
= 353/2 (4 + 708)
= 353/2 × 712
= 353 × 712/2
= 251336/2 = 125668
Thus, the sum of all terms of the given even numbers from 4 to 708 = 125668
And, the total number of terms = 353
Since, the average of the given numbers
= Sum of the given numbers/Total number of given numbers
Thus, the average of the given even numbers from 4 to 708
= 125668/353 = 356
Thus, the average of the given even numbers from 4 to 708 = 356 Answer
Similar Questions
(1) Find the average of the first 4517 even numbers.
(2) Find the average of even numbers from 6 to 1456
(3) Find the average of even numbers from 4 to 904
(4) Find the average of the first 2846 odd numbers.
(5) Find the average of even numbers from 4 to 1244
(6) Find the average of odd numbers from 9 to 67
(7) Find the average of the first 3571 even numbers.
(8) Find the average of even numbers from 12 to 1748
(9) Find the average of odd numbers from 13 to 633
(10) Find the average of odd numbers from 15 to 647