d$.$ For subscribers, assume that the marketing expenses are allocated such that, on average per customer, $$20$ is allocated to acquiring new readers and nothing is spent on retaining existing readers. Furthermore, assume that the retention rate of subscribers is $100$ percent over the course of one year. What subscription price would leave the customer period value for a subscriber equal to that of a newsstand reader?

e$.$ From this analysis alone, what range of prices would you expect to see for an annual subscription to the FT$?$

f$.$ The FT offers an annual subscription at $$99.$ Does this price lie within the range predicted from this analysis? If not, how would you account for the difference?

Hint: Consider the effect of two$-$sided markets on subscription prices.