请教NN！谢谢

scholar

A certain library assesses fines for overdue books as follows . On the first day that a book is
overdue, the total fine is $0.1.For each additional day that a book is overdue ,the total fine is
either increased by $o.3 or doubled,whichever results in the lesser amount.
What is the total fine for abook on the fourth day it is overdue? $0.7

king12wolf

题目说第一天是0.1  第二天开始要么比前一天多0.3  要么double   然后选低的那个  所以第一天0.1  第二天0.2 第三天 0.4 第四天0.7

jack3939889

First day   0.1

second day    0.1+0.3   OR   0.1*2

third day   (0.1+0.3)+0.3  or  (0.1+0.3)*2  OR (0.1*2)+0.3   or (0.1*2)*2  

4th  0.7*2 or 0.7+0.3  or 0.8*2  or 0.8+0.3   or  0.5*2 or 0.5+0.3 or 0.4*2  or 0.4+0.3=0.7(People will choose the smallest fine)