Question

Evaluate 12 sigma n=3 20(0.5)^n-1
9.99
19.95
29.98
39.96

Answer 1

Answer: Is D

Explanation:

Answer 2

We have a geometric series in which:

a = 20

r = 1/2

Now, we know that: S2 = 20(1-r^2)/(1-r) and S12 = 20(1-r^12)/1-r

Therefore: sigma(3,12) = S12-S2 = 20[(1-r^12)/(1-r) - (1-r^2)/(1-r)] =5115/512 = 9.99023438

Therefore, the answer is: 9.99