Hello there. To solve this question, we'll have to remember some properties about percents.
We start with percent of increase: it is the difference between how much a thing is from another and 100%.
Now, to calculate this amount, we take the ratio of the numbers. In this case, the cost of a pound of nails.
Knowing it increased from $2.03 to $2.19, we calculate:
2.19/2.03 = 1.079
Multiply by 100% to find its amount in percent
1.079 * 100% = 107.9%
Now, we simply take the difference:
107.9% - 100% = 7.9%
Rounding this percent to the nearest whole-number percent, we get:
8%