Qian used the rule “divide the length of a piece of wood by 3 to get the number of nails needed.” If 3 nails are needed for a piece of wood that is 9 inches and 13 nails are needed for a piece of wood that is 39 inches, what is the length of a piece of wood that requires 8 nails? (1 point) Responses 18 inches 18 inches 21 inches 21 inches 24 inches 24 inches 27 inches
Let's use the given information to set up a proportion and find the length of wood that requires 8 nails.
We know that for every 9 inches of wood, 3 nails are needed. So, we can write the first proportion as:
9 inches / 3 nails = X inches / 8 nails
Cross-multiplying gives us:
3 nails * X inches = 8 nails * 9 inches
3X = 72
Simplifying further, we find:
X = 72 / 3
X = 24
Therefore, a piece of wood that requires 8 nails has a length of 24 inches.