The sequence x1, x2, x3,..., is such that Xn = 1/n - (1/(n+1)). What is the sum of the first 20 terms of the sequence?
Pick:
A) 201/100
B) 99/100
C) 100/101
D) 1/10000
E) 20/21
Easy task and accomplish   X1=1-1/2   x2=1/2-1/3   x3=1/3-1/4   .....   x20=1/20-1/21   sum=X1+X2+X3+....X20=1-1/2+1/2-1/3+.......1/20-1/21=1-1/21=20/21   20/21 is the answer
<result>E</result>
The sequence x1, x2, x3,..., is such that Xn = 1/n - (1/(n+1)). What is the sum of the first 20 terms of the sequence?