Answer:
Small box weighs 35 pounds.
Large box weighs 40 pounds.
Step-by-step explanation:
Let the weight of a small box be x and the weight of the large box be y pound:
x + y = 75
60x + 70y = 4900
6x + 7y = 490 ............A
Mulyiply the first equation by 6:
6x + 6y = 450 ..............B
Subtract equation A - equation B:
y = 40 so the large box weighs 40 pounds.
Substitute y = 40 into x + y = 75:
x + 40 = 75
x = 75 - 40
x = 35 .