One pack of a vaccine contains 32 vials. How many vials are in 18 packs?

To find the total number of vials in 18 packs of vaccine, you need to multiply the number of vials per pack by the number of packs. Since each pack contains 32 vials, you will perform the calculation:

32 vials/pack × 18 packs = 576 vials.

This calculation confirms that the total number of vials in 18 packs is 576. Therefore, the correct answer is 576 vials.

This method of multiplying the quantity in one unit by the number of units is a fundamental principle in arithmetic, showing how to scale a singular measure to a larger quantity efficiently.