Final answer:
The equation that could be used to determine the cost in dollars, d, of x nails is option D: d = cx/100n. The equation involves converting the cost from cents to dollars, and then dividing by the number of nails in a set.
Step-by-step explanation:
The equation that could be used to determine the cost in dollars, d, of x nails is option D, which is d = cx/100n.
To understand why option D is correct, let's break down the equation:
d represents the cost in dollars, x represents the number of nails, c represents the cost in cents, and n represents the number of nails in a group or set that has a certain cost.
To convert the cost from cents to dollars, we divide by 100, hence the cx/100 in the equation.
Finally, to determine the cost of x nails, we divide the total cost by the number of nails in a set, which is why we have the x/100n in the equation.