The probability of getting heads on the first toss is 1/2 .
Then, the probability of getting heads on the second toss is 1/2 .
Then, the probability of getting heads on the third toss is 1/2 .
The probability of all three things happening is ...
(1/2) x (1/2) x (1/2) = 1/8 = 0.125 = 12.5% .
18.56, 18.57, 18.58 or 18.59?

As

, the sequence

converges to zero.
If you're talking about the infinite series

well we've shown by comparison that this series must also converge because we know any geometric series

will converge as long as

.
Answer: 19 + 3x
Step-by-step explanation:
Given : 4 + 3(5+x)
expanding , we have
4 + 15 + 3x
= 19 + 3x
Therefore :
4 + 3 ( 5 + x ) = 19 + 3x