Question

Mass box A = 10 grams; Mass box B = 5 grams; Mass box C—made of one A and one B

How many boxes of A would be required to make 30 grams of C?

Answer 1

2 boxes of A
Because C=A+B
2 of A = 20 grams
at the other hand we have 2 of B =10
So 20 + 10 = 30 grams