Answer:
see below
Step-by-step explanation:
The sum of an infinite series with first term "a" and common ratio "r" is ...
S = a/(1 -r) . . . . . for |r| < 1
Then the sums for the given answer choices are ...
A: 5/(1 -3/4) = 20 . . . . . the answer of choice
B: 4/(1 -5/6) = 24
C: 4/(1 -1/5) = 5
D: 10/(1 -1/5) = 12.5
