show me this, I do not understand: Total time to test one batch: ( 9 \text{ minutes} + (15 \text{ Duos} \times 0.2 \text{ minutes per Duo}) = 12 \text{ minutes} ). Number of Duos tested per hour: ( \frac{60 \text{ minutes}}{12 \text{ minutes per batch}} \times 15 \text{ Duos per batch} = 75 \text{ Duos} ). Number of Duos tested per shift: ( 75 \text{ Duos per hour} \times 8 \text{ hours} = 600 \text{ Duos} ). Number of Duos tested per day (3 shifts): ( 600 \text{ Duos per shift} \times 3 \text{ shifts} = 1800 \text{ Duos}