Question

find the average of first 20 multiples of 3​

Answer 1

Answer:

average =

3+6+9+12+15+18+21+24+27+30+33+36+39+42+45+48+51+54+57+60/20

=630/20

=31.5

Answer 2

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)

=$3*\frac{20*(20+1)}{2}${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.