Question

find the sum of the first 20 multiple of 4 please let me know step by step answer​

Answer 1

Answer:

31.5

Step-by-step explanation:

The first 20 multiples of 3 are 3, 6, 9, 12,......, 60.

The sum of those multiples is given by  

3+6+9+12+15+.....+60

=3(1+2+3+4+.....+20)

=3*\frac{20*(20+1)}{2}3∗220∗(20+1) {Since, sum of n natural numbers stating from 1 is given by n(n+1)/2}

=3×210

=630  

Hence, the average of  those multiples will be 630/20=31.5.

Therefore, the average of the first 20 multiples of 3 will be 31.5.

Step-by-step explanation:

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