In section 15.2, Keynes elaborates on the idea that the different motives informing liquidity-preference are influenced differently by different factors.He says that , the money savings corresponding to the transaction-motive and precautionary-motive, is determined by a function () of income (). He then says that , as the savings corresponding to the speculative-motive, is determined by a function () of the interest rate (). Thus, the total amount of savings in money () is jointly determined by the sum of the categories of savings: