Answer: Bob used 50% of rope
Explanation:
Let's begin by converting inches to feet
if
1foot =12inches
X foot =18 inches
Crosss multiplying we have
X foot =18/12
X=1.5 feet
18 inches is 1.5feet
We can also say Bob the builder used 1.5feet of 3 feet of rope
To get the percentage
1.5/3*100=
0.5*100=50%