I'm trying to understand a solution to a problem from Analysis for Financial Management (11th Edition) Ch 4, Q. 4P and I can't understand how you got the retention ratio? The question starts with"Table 3.1 in the last chapter presents R& E's Supplies ' financial statements for the period of 2014 through 2017, and table 3.5 presents a proforma financial forecast for 2018"Use the information in these tables to answer:

a)Calculate R&E's sustainable growth rate each year from 2015 to through 2018

b)Comparing the company's sustainable growth rate with with its actual and projected growth sales over these years, what growth management problems does R&E appear to face in this period?

c)How did the company cope with these problems? Do you see any difficulties with the way it addressed its growth problems over this period? If so, what are they?

d)What advice would you offer management regarding managing future growth?

The solution has been posted, but how did you get the retention ratio?