Charlie poured pancake mixture into two types of containers with different capacities as shown below. He poured half the mixture into big containers and the other half of it into small containers. He filled the containers to the brim. Charlie used 24 more small containers than big containers.

1. Determine the ratio of the number of small containers to big containers needed for the same volume.

Since half the mixture is in big containers and half in small containers, the total volume in both types of containers is the same.
Ratio of capacity of 1 big container to 1 small container = $375 : 75 = 5 : 1$.
For the same volume, the ratio of the number of big containers to small containers is $1 : 5$.

2. Use the difference in the number of containers to find the number of big containers.

Difference in ratio units = $5 - 1 = 4$ units.
$4$ units = $24$ containers.
$1$ unit = $24 \div 4 = 6$ containers.
Number of big containers = $1$ unit = $6$.

1. Find the number of big containers used (from part a)

Let $B$ be the number of big containers and $S$ be the number of small containers.
Since half the mixture is in big containers and half in small containers, the total volume in big containers equals the total volume in small containers.
$375 \times B = 75 \times S$
$S = 5B$
We are given $S = B + 24$.
$5B = B + 24$
$4B = 24 \implies B = 6$

2. Calculate the volume of half the mixture

Volume in big containers = $6 \times 375 = 2250$ ml

3. Calculate the total volume of the mixture

Total volume = $2250 \times 2 = 4500$ ml