Answer
54.5%
Step-by-step explanation
= (49.03÷89.97)*100
= 54.50%
Therefore, the watch that Amazon is currently selling is worth $89.97 as per its cost and after charging a mark-up percentage of 64.73%, Amazon is selling the stop watch for $139. The mark-up is being calculated by putting the profit of the watch as the percentage of the cost of the watch.