Mobile site cost benefit analysis

Assignment: Formulate a position on the decision as to whether to make the $50,000 investment in the development of a mobile friendly web site. Defend your decision using the data, assumptions,  and financial calculations. 
Show your analysis (numbers). Explain your assumptions. Project the financial impact of making the investment. 
Not more than one page of writing … but as many numbers as you’d like. 

Situation: The Micromark web site currently is not mobile friendly. Customers that visit the site via mobile devises need to “pinch” the screen to see what is on the page. Technology exists that can optimize the user experience for the devise the customer is using. 
I have received an estimate from our IT service that maintains our site platform. The cost of a state of the art “responsive design” platform is $50,000 (one time cost ... no additional recurring expense) 
I have provided the following information: 
•Historical Web Metrics
•Google search traffic 
•Web P&L
•Articles 
•Micromark retention rates