Answer:
25%
Explanation:
500 bumper stickers sold in the first week is 100%. The bumper stickers sold in the second week is 50% more (150%).
500 / 100 = x / 150
x = 750
750 bumper stickers sold in the second week is 100%. The bumper stickers sold in the third week is 50% less (50%).
750 / 100 = x / 50
x = 375
The bumper stickers sold in the third week as a percentage of the bumper stickers sold in the first week is:
375 / 500 = x / 100
x = 75
The bumper stickers sold in the third week is 75% of the bumper stickers sold in the first week, which means there was a 25% decrease.