A big box can hold 12 marbles. A small box can hold 6 marbles. 84 marbles are to be placed into 10 boxes. How many big boxes are there? How many small boxes are there?
12 b = big box marbles
6(10-b) = small box marbles summed = 84
12b + 6(10-b) = 84
b = big boxes = 4 then little boxes = 10-4 = 6 little boxes