A marketer of a medication is willing to invest in the acquisition of new patients. What would be the upper limit of this investment per patient assuming the follow retention/attrition rate and assumptions? Should the marketer spend an additional $2.00 per month to reduce the attrition rate by 2% per month (e.g. 95.10 instead of 93.10 or 89.40 instead of 87.40 in the first two months)? Assumptions: 1. Revenue per patient per month=$250 2. Medications are paid for at the end of the month 3. Internal rate of return of 18% compounded monthly. Retention rate for a typical cohort Month Retention

Month 0 100.00

Month 1 93.10

Month 2 87.40

Month 3 82.82

Month 4 79.32

Month 5 77.29

Month 6 75.30

Month 7 73.36

Month 8 71.46

Month 9 69.70

Month 10 67.98

Month 11 65.50

Month 12 63.95