Final answer:
Devon will be making 3.75 liters of soup for the party.
Step-by-step explanation:
To convert milliliters to liters, we divide the number of milliliters by 1000. In this case, Devon makes 375 milliliters of soup per person, so we can multiply 375 by 100 to get the total milliliters of soup she needs to make for 100 guests. Then, we divide the result by 1000 to convert it to liters. Therefore, Devon will be making 3.75 liters of soup for the party.