Question:
Find the average of even numbers from 6 to 1988
Correct Answer
997
Solution And Explanation
Solution
Method (1) to find the average of the even numbers from 6 to 1988
Shortcut Trick to find the average of the given continuous even numbers
The even numbers from 6 to 1988 are
6, 8, 10, . . . . 1988
After observing the above list of the even numbers from 6 to 1988 we find that the difference between two consecutive terms are equal. This means the list of the even numbers from 6 to 1988 form an Arithmetic Series.
In the Arithmetic Series of the even numbers from 6 to 1988
The First Term (a) = 6
The Common Difference (d) = 2
And the last term (ℓ) = 1988
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 6 to 1988
= 6 + 1988/2
= 1994/2 = 997
Thus, the average of the even numbers from 6 to 1988 = 997 Answer
Method (2) to find the average of the even numbers from 6 to 1988
Finding the average of given continuous even numbers after finding their sum
The even numbers from 6 to 1988 are
6, 8, 10, . . . . 1988
The even numbers from 6 to 1988 form an Arithmetic Series in which
The First Term (a) = 6
The Common Difference (d) = 2
And the last term (ℓ) = 1988
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 6 to 1988
1988 = 6 + (n – 1) × 2
⇒ 1988 = 6 + 2 n – 2
⇒ 1988 = 6 – 2 + 2 n
⇒ 1988 = 4 + 2 n
After transposing 4 to LHS
⇒ 1988 – 4 = 2 n
⇒ 1984 = 2 n
After rearranging the above expression
⇒ 2 n = 1984
After transposing 2 to RHS
⇒ n = 1984/2
⇒ n = 992
Thus, the number of terms of even numbers from 6 to 1988 = 992
This means 1988 is the 992th term.
Finding the sum of the given even numbers from 6 to 1988
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 6 to 1988
= 992/2 (6 + 1988)
= 992/2 × 1994
= 992 × 1994/2
= 1978048/2 = 989024
Thus, the sum of all terms of the given even numbers from 6 to 1988 = 989024
And, the total number of terms = 992
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 6 to 1988
= 989024/992 = 997
Thus, the average of the given even numbers from 6 to 1988 = 997 Answer
Similar Questions
(1) Find the average of the first 3658 even numbers.
(2) Find the average of odd numbers from 11 to 441
(3) Find the average of odd numbers from 7 to 1091
(4) Find the average of the first 3218 odd numbers.
(5) Find the average of the first 3038 odd numbers.
(6) Find the average of odd numbers from 3 to 1085
(7) Find the average of odd numbers from 9 to 1057
(8) Find the average of even numbers from 10 to 1660
(9) Find the average of the first 4166 even numbers.
(10) Find the average of even numbers from 10 to 494