Math exercise: I lend you a million pesos. On day 1 you pay me 1 peso of that million, on day 2 you pay me 2 pesos, on day 3 you pay me 4 pesos, on day 4 you pay me 8, on day 6 you pay me 32. 1. analyze how the payments will go until the 30th and 2. see if you accept or not the deal to see if it suits you