Question:
Find the average of even numbers from 8 to 246
Correct Answer
127
Solution And Explanation
Solution
Method (1) to find the average of the even numbers from 8 to 246
Shortcut Trick to find the average of the given continuous even numbers
The even numbers from 8 to 246 are
8, 10, 12, . . . . 246
After observing the above list of the even numbers from 8 to 246 we find that the difference between two consecutive terms are equal. This means the list of the even numbers from 8 to 246 form an Arithmetic Series.
In the Arithmetic Series of the even numbers from 8 to 246
The First Term (a) = 8
The Common Difference (d) = 2
And the last term (ℓ) = 246
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 8 to 246
= 8 + 246/2
= 254/2 = 127
Thus, the average of the even numbers from 8 to 246 = 127 Answer
Method (2) to find the average of the even numbers from 8 to 246
Finding the average of given continuous even numbers after finding their sum
The even numbers from 8 to 246 are
8, 10, 12, . . . . 246
The even numbers from 8 to 246 form an Arithmetic Series in which
The First Term (a) = 8
The Common Difference (d) = 2
And the last term (ℓ) = 246
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 8 to 246
246 = 8 + (n – 1) × 2
⇒ 246 = 8 + 2 n – 2
⇒ 246 = 8 – 2 + 2 n
⇒ 246 = 6 + 2 n
After transposing 6 to LHS
⇒ 246 – 6 = 2 n
⇒ 240 = 2 n
After rearranging the above expression
⇒ 2 n = 240
After transposing 2 to RHS
⇒ n = 240/2
⇒ n = 120
Thus, the number of terms of even numbers from 8 to 246 = 120
This means 246 is the 120th term.
Finding the sum of the given even numbers from 8 to 246
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 8 to 246
= 120/2 (8 + 246)
= 120/2 × 254
= 120 × 254/2
= 30480/2 = 15240
Thus, the sum of all terms of the given even numbers from 8 to 246 = 15240
And, the total number of terms = 120
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 8 to 246
= 15240/120 = 127
Thus, the average of the given even numbers from 8 to 246 = 127 Answer
Similar Questions
(1) Find the average of even numbers from 10 to 1808
(2) Find the average of the first 2929 even numbers.
(3) What is the average of the first 1886 even numbers?
(4) What will be the average of the first 4831 odd numbers?
(5) What is the average of the first 1830 even numbers?
(6) Find the average of the first 2049 odd numbers.
(7) Find the average of the first 822 odd numbers.
(8) Find the average of odd numbers from 3 to 1217
(9) Find the average of odd numbers from 11 to 235
(10) Find the average of odd numbers from 15 to 891