How many boxes of a would be required to make 30 grams of c

If we're referring to mass - you would require the following:

15g of A

15g of B.

So, 1.5 boxes A, 3 boxes B.

If we're talking about volume, 20g A and 10g B.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.