Answer:
B. 12.5%
Step-by-step explanation:
Find how much was unused:
120 - 105
= 15
To find what percent this is, divide it by 120:
15/120
= 0.125
Multiply this by 100:
0.125(100)
= 12.5
So, 12.5% of the wire went unused
The correct answer is B. 12.5%
