Answer: 92
Step-by-step explanation:
So 12 +80 = 4(3 + 20) = 92
You found $5, so it's positive. You don't put anything in the negative, because you aren't losing anything.
Answer:
25.5 days
Step-by-step explanation:
Mean number of days (μ) = 22 days
Standard deviation (σ) = 6 days
Z-score for the 72nd percentile (according to tabulated values) = 0.583
The z-score for any number of days, X, is determined by:

The value of X that is greater than 72% of the trial times is:

Therefore, 72% of all of these types of trials are completed within 25.5 days.
I think the answer is 17.5 years