A mini-calculator company saw its sales decrease over the last year and decided to launch a new marketing mix strategy to boost awareness and sales. One of the company’s implemented tactics was to sell its mini-calculators through Amazon. It spent $5,000 to add new colors to their product offerings and $5,000 launching a video ad campaign. After tracking its online sales metrics, it saw a leap in sales of $20,000 in three months. What is this company's ROI on their marketing efforts?