Question 9

2.5 mL will last for 12 days.

To determine how many days the 2.5 mL of eyedrops will last when used once daily in each eye, we first calculate the total number of drops available. With 15 drops per mL, 2.5 mL provides 37.5 drops. Since two drops are used each day (one for each eye), the drops will last for 12 days.

A) 6

This option is incorrect because if each day requires two drops, the total number of drops from 2.5 mL does not support only 6 days of usage. Six days would only account for 12 drops, which is less than the total available.

B) 12

This option is correct as it accurately reflects the calculation based on the total available drops. With 2.5 mL yielding 37.5 drops and using 2 drops per day, the drops last exactly 12 days.

C) 18

This option is incorrect because it suggests a longer duration than is possible with the given volume of drops. Using 18 days would require 36 drops, which exceeds the number of drops available from 2.5 mL.

D) 36

This option is incorrect as it implies a much greater number of days than the available drops can support. To last 36 days, 72 drops would be needed, which is well beyond the 37.5 drops obtainable from 2.5 mL.

Conclusion

The correct answer is 12 days, as it matches the calculation of the total drops available against the daily usage. All other options fail because they either understate or overstate the number of days based on the total drops derived from the prescription volume.