Question

The average of 13 consecutive numbers is 324. If there is another series which starts with the same number as the previous series, then what is the average of the first 20 consecutive numbers of the series ?

Answer 1

let the no be a-6d,a-5d,a-4d,a-3d,a-2d,a-d,a-a+d,a+2d,a+3d,a+4d,a+5d,a+6d
s0
13a/13=324
so a=324
now 20 number
a-d,a+d,a-3d,a+3d,a-5d,a+5d,a-7d,a+7d,a-9d,a+9d,a+11d,a-11d,a+13d,a-13d,a+15d,    a-15d,a-17d,a+17d,a+19d,a-19d
so 
20a/2a=324
so a=324