First, multiply the two types of bottles separately.
5 × 400 = 2000 mL
7 × 1.5 = 10.5 L
You can convert the volume of the first from milliliters to liters. There are 1000 milliliters in 1 liter. In the second volume, you can convert the decimal to milliters.
The first thing we want to do is times 5 times 400 = 2000 and 7 times 1.5L = 10.5 to convert L to mL we get 10500 add those together and we get 12500 ML converted we get 12.5 L!