Respuesta :

lisa391199
One weighs 18.1 pounds.
surferninjagirl

Answer:

Step-by-step explanation:

Let B = the weight of box B

Let 2B = the weight of box A

Let 2B + 30 = the weight of box C

B + 2B + 2B + 30 = 640

5B = 610

B = 122 pounds, weight of box B

2B = 2(122) = 244 pounds, weight of box A

2B + 30 = 2(122) + 30 = 274 pounds, weight of box C