Pages 33

Incidentally, for the case in which ()' p > r, the reader is referred to a more elaborate formula, (14: 52) (Guide­ lines, p. 197) which, as it happens, does not work for ()' equal to unity - for the case, that is, in which all returns to private investment are continually and wholly reinvested. A moment's reflection on this case suggests that it can easily be managed by using p as the discount rate in the investment criterion.