Answer:
Explanation:
Let the number of small boxes is s and number of large boxes is l.
s and l are our variables.
Total number of boxes is 21:
This is your first equation.
The volume of a small box is a (since it is not given, if you have it please replace it with that number), and the volume of all small boxes is as.
The volume of a larger box is 14 cubic feet, and the volume of all large boxes is 14l cubic feet.
Total volume is 252 cubic feet, add the two volumes together:
And this is your second equation (don't forget to replace a with the volume of a small box).