Rille has had her neighbor mow the lawn all summer when Rille has been on a long holiday in Provence and according to information, Rille would pay SEK 200 per mowing during June, July and August. Upon returning home, Rille can see in his messages that the lawn has been mowed 20 times, which corresponds to SEK 4,000 to pay to the neighbor. The problem for Rille now is that he spent his last pennies on foam in Nice when he was on his way home, and would have to pay a little later, preferably in two months as there are other old bills from the summer at home on the kitchen table

However, Rille works in the financial industry and assesses that the neighbor has the following value differences after observing how the neighbor reasons:

2 * v (4000) = v (7500)

Then Rille asks the neighbor, "if I were to pay you SEK 7,500 in the future instead of SEK 4,000 today, how long can I wait to pay then?"

The neighbor thinks for a minute and says: "Eh, then I could wait until June next year, so nine months".

Aha, Rille thinks, what will Rille suggest he pay his neighbor two months later instead of nine months later enlighten the Harvey model?