Answer:
The first one
Step-by-step explanation:
Since only the first session is $10, it wouldn't be 10x.
The second session is $5, and it will never be $10 again, so $5 sessions are unlimited which would be 5x.
So the answer is y = 10 + 5x
(sorry if i didnt explain well)
100,000 doubles to 200,000 in 80 years then 400,000 in 80 more years
49
-3√(t) = -21
√(t) = 7
t = 49
246.36
