Answer:
Percent Increase
Explanation:
Percent Increase because if the necklace was bought for $260, and was marked up by 30%, it means it was originally a lower price, that was multiplied by 130%.
Explanation by algebra:
x + 0.30x = 260
1.3x = 260
x = 260/1.3
x = 200
The necklace was originally $200, and it was marked up by 30$, making it $260.