Question:
Find the average of the first 2640 even numbers.
Correct Answer
2641
Solution And Explanation
Explanation
Method to find the average
Step : (1) Find the sum of given numbers
Step: (2) Divide the sum of given number by the number of numbers. This will give the average of the given numbers
The first 2640 even numbers are
2, 4, 6, 8, . . . . 2640 th terms
Calculation of the sum of the first 2640 even numbers
We can find the sum of the first 2640 even numbers by simply adding them, but this is a bit difficult. And if the list is long, it is very difficult to find their sum. So, in such a situation, we will use a formula to find the sum of given numbers that form a particular pattern.
Here, the list of the first 2640 even numbers forms an Arithmetic series
In an Arithmetic Series, the common difference is the same. This means the difference between two consecutive terms are same in an Arithmetic Series.
The sum of n terms of an Arithmetic Series
Sn = n/2 [2a + (n – 1) d]
Where, n = number of terms, a = first term, and d = common difference
In the series of the first 2640 even number,
n = 2640, a = 2, and d = 2
Thus, sum of the first 2640 even numbers
S2640 = 2640/2 [2 × 2 + (2640 – 1) 2]
= 2640/2 [4 + 2639 × 2]
= 2640/2 [4 + 5278]
= 2640/2 × 5282
= 2640/2 × 5282 2641
= 2640 × 2641 = 6972240
⇒ The sum of the first 2640 even numbers (S2640) = 6972240
Shortcut Method to find the sum of the first n even numbers
Thus, the sum of the first n even numbers = n2 + n
Thus, the sum of the first 2640 even numbers
= 26402 + 2640
= 6969600 + 2640 = 6972240
⇒ The sum of the first 2640 even numbers = 6972240
Calculation of the Average of the first 2640 even numbers
Formula to find the Average
Average = Sum of the given numbers/Number of the numbers
Thus, The average of the first 2640 even numbers
= Sum of the first 2640 even numbers/2640
= 6972240/2640 = 2641
Thus, the average of the first 2640 even numbers = 2641 Answer
Shortcut Trick to find the Average of the first n even numbers
(1) The average of the first 2 even numbers
= 2 + 4/2
= 6/2 = 3
Thus, the average of the first 2 even numbers = 3
(2) The average of the first 3 even numbers
= 2 + 4 + 6/3
= 12/3 = 4
Thus, the average of the first 3 even numbers = 4
(3) The average of the first 4 even numbers
= 2 + 4 + 6 + 8/4
= 20/4 = 5
Thus, the average of the first 4 even numbers = 5
(4) The average of the first 5 even numbers
= 2 + 4 + 6 + 8 + 10/5
= 30/5 = 6
Thus, the average of the first 5 even numbers = 6
Thus, the Average of the First n even numbers = n + 1
Thus, the average of the first 2640 even numbers = 2640 + 1 = 2641
Thus, the average of the first 2640 even numbers = 2641 Answer
Similar Questions
(1) Find the average of the first 498 odd numbers.
(2) What is the average of the first 270 even numbers?
(3) Find the average of the first 2006 even numbers.
(4) Find the average of the first 3244 odd numbers.
(5) What is the average of the first 286 even numbers?
(6) What will be the average of the first 4191 odd numbers?
(7) Find the average of even numbers from 10 to 1114
(8) Find the average of even numbers from 4 to 1662
(9) Find the average of even numbers from 12 to 562
(10) What will be the average of the first 4509 odd numbers?