Let $L$ be the number of large figurines and $S$ the number of small figurines.

Total figurines: $L + S = 40$

Revenue from large equals revenue from small:

$12L = 4S$

From the revenue equation: $S = 3L$. Substitute into the total:

$L + 3L = 40$

$4L = 40$

$L = 10$

Reed sold $10$ large figurines.