This problem is a simple percent chage problem. The absoluge change in price was $12−$8=$4. Relative to the original price, it was 412, which is 0.3333 or 33.33%.
(new- original)/original * 100 percent
(100-8)/8 * 100 percent
92/8 * 100 percent
11.5 * 100 percent
1150 percent
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