Answer:
Step-by-step explanation:
Original cost = $55
Current price = $40
Decrease in price = 40-55 = -$15
Percentage decrease = [(New price - old price)/ old price] *100
Percentage decrease = (40-55)/55] *100
= -0.272727 *100
= -27.27%
To a whole percentage = 27%
Therefore, the cost of the t-shirt decreased by 27%
