Question

how many times 2 must be added to 8 to obtain 1024

Answer 1

Let a=8,
 d = 2,
and a(n) = 1024

∴ a(n) = a +(n-1)d
⇒1024 = 8 +(n-1)2
⇒1016/2 = n-1
⇒508+1 = n
⇒n = 509

∴2 must be added 509 times to get 1024 

Answer 2

First subtract 8 from 1024
1024-8= 1016.
Then divide it by 2.
1016/2= 508.
Therefore 2 should be added 508 times.