The layer of gold coating on a ring should be 0.03 millimeters thick when the ring is completed. A coating of 0.021 millimeters
has already been applied. How many more millimeters of gold coating must be added to finish the ring? A.) 0.018 millimeters
B.) 0.009 millimeters
C.) 0.18 millimeters
D.) 0.09 millimeters
The amount of gold coating in millimeters needed for the ring is the difference between the total coating and the coating that has already been applied. From the given above, that would be, 0.03 mm - 0.021 mm = 0.009 mm Thus, the answer to this question is letter B.
