Adam should invest $15516 after 18 years.
Step-by-step explanation:
Given:
Amount(18) = $20000
Rate of Interest, r = 1.41%
Time, t = 18 years
n = 365 (compounded daily)
General equation of amount that is compounded daily:

Solving for A₀:

Substituting the values:

Therefore, Adam should invest $15516 after 18 years.