PREP数学
A certain library assesses fines for overdue books as follows: On the first day that a book is overdue, the total fine is $0.10; For each additional day that the book is overdue, the total fine is either increased by $0.30 or doubled, whichever results in the lesser amount. What is the total fine for a book on the fourth day it is overdue?
$0.60
$0.70
$0.80
$0.90
$1.0
KEY:$0.70
我做的是0.1+0.3*3=1
0.1*2*2*2=0.8
所以选$0.80
请指教!
