Question 854204
1/1024= 1/2 * 1/2^(n - 1)
n=10
S=1/2*(1 - 1/2^10)/(1 - 1/2)
S=1023/1024 which is almost 1
We know that it must be more than 3/4 since just  the first two terms are 1/2+1/4 which is 3/4.
The other tutor's answer 
1023/4096 is less than 1/4