Let the weight of the full Volume of nails in the box be W.
Let the weight of the box be B.
2/3 W + B = 130 ........i From the first statement.
3/8 W + B = 74 ......ii From the second statement.
Equation (i) Minus (ii)
2/3 W - 3/8 W + B - B = 130 - 74
(16W - 9W) / 24 = 56
7W / 24 = 56.
W = 56 * 24 / 7
W = 192 Pounds.
Substituting V = 64 in equation (i)
2/3 W + B = 130
2/3 * 192 + B = 130
2 * 64 + B = 130
128 + B = 130
B = 130 -128 = 2.
Therefore, weight of box, B = 2 pounds.
It was hard to figure this put but I'll just a take an educated guess and say that the answer is 10%.
Your answer would be A)
Hope this helps (:
You have to use the y=mx+b formula to find the equation