#### Explanation:

Unit of time is 3 years. Answer $$20 \left({\left(1 - 0.5\right)}^{3} \left(1 - \frac{0.5}{3}\right)\right) M i l l i o n$=$2083333
Multiplication by ( 1 - 0.5/3) is for the period 1 year, after 3 3-year units.