Problem Solving

Q. A certain library assess fines for overdue books as follows. On the first day that a book was 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?

A. $0.60
B. $0.70
C. $0.80
D. $0.90
E. $1.00

Ans: B

Just follow the terms of the question, one day at a time:

1st day: fine is $0.1

2nd day:
either raise by 0.3 to get 0.1+0.3=$0.4
OR
double the fine to get 0.1*2=$0.2

The questions states to choose the lesser amount, so we go with the second option. Fine is now $0.2

3rd day:
either raise by 0.3 to get 0.2+0.3=$0.5
OR
double the fine to get 0.2*2=$0.4

The questions states to choose the lesser amount, so we go with the second option. Fine is now $0.4

4th day:
either raise by 0.3 to get 0.4+0.3=$0.7
OR
double the fine to get 0.4*2=$0.8

The questions states to choose the lesser amount, so we go with the first option. Fine is now $0.7. Answer is B.

Got it, I lost the problem with the "and" / "or" condition and ended up using either increments of 0.3 or doubling it up. Thanks.

Geva@MasterGMAT wrote:Just follow the terms of the question, one day at a time:

1st day: fine is $0.1

2nd day:
either raise by 0.3 to get 0.1+0.3=$0.4
OR
double the fine to get 0.1*2=$0.2

The questions states to choose the lesser amount, so we go with the second option. Fine is now $0.2

3rd day:
either raise by 0.3 to get 0.2+0.3=$0.5
OR
double the fine to get 0.2*2=$0.4

The questions states to choose the lesser amount, so we go with the second option. Fine is now $0.4

4th day:
either raise by 0.3 to get 0.4+0.3=$0.7
OR
double the fine to get 0.4*2=$0.8

The questions states to choose the lesser amount, so we go with the first option. Fine is now $0.7. Answer is B.