Question:
Find the average of the first 3200 even numbers.
Correct Answer
3201
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 3200 even numbers are
2, 4, 6, 8, . . . . 3200 th terms
Calculation of the sum of the first 3200 even numbers
We can find the sum of the first 3200 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 3200 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 3200 even number,
n = 3200, a = 2, and d = 2
Thus, sum of the first 3200 even numbers
S3200 = 3200/2 [2 × 2 + (3200 – 1) 2]
= 3200/2 [4 + 3199 × 2]
= 3200/2 [4 + 6398]
= 3200/2 × 6402
= 3200/2 × 6402 3201
= 3200 × 3201 = 10243200
⇒ The sum of the first 3200 even numbers (S3200) = 10243200
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 3200 even numbers
= 32002 + 3200
= 10240000 + 3200 = 10243200
⇒ The sum of the first 3200 even numbers = 10243200
Calculation of the Average of the first 3200 even numbers
Formula to find the Average
Average = Sum of the given numbers/Number of the numbers
Thus, The average of the first 3200 even numbers
= Sum of the first 3200 even numbers/3200
= 10243200/3200 = 3201
Thus, the average of the first 3200 even numbers = 3201 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 3200 even numbers = 3200 + 1 = 3201
Thus, the average of the first 3200 even numbers = 3201 Answer
Similar Questions
(1) What is the average of the first 86 even numbers?
(2) Find the average of the first 2541 odd numbers.
(3) Find the average of even numbers from 8 to 260
(4) Find the average of the first 2276 odd numbers.
(5) Find the average of the first 3281 even numbers.
(6) Find the average of even numbers from 12 to 1000
(7) What is the average of the first 482 even numbers?
(8) Find the average of the first 4673 even numbers.
(9) Find the average of even numbers from 12 to 442
(10) What will be the average of the first 4533 odd numbers?