Final answer:
One box of Lantus insulin pens will last for 30 days.
Step-by-step explanation:
To calculate how many boxes of Lantus insulin pens will be needed, we need to find out how many mL are required in total. The prescription requires injecting 50 units once daily, and each mL of Lantus insulin pen contains 100 units. So, 50 units is equivalent to 0.5 mL.
One box of Lantus insulin pens contains 5 pens, and each pen contains 3 mL. Therefore, one box contains a total of 15 mL (5 pens x 3 mL/pen = 15 mL/box).
Since 0.5 mL is required per day, we can divide the total number of mL in a box (15 mL) by the number of mL required per day (0.5 mL/day) to find out how many boxes are needed. 15 mL / 0.5 mL/day = 30 days, which means one box of Lantus insulin pens will last for 30 days.