A certain library

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 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

Notice that, fines are already cumulative: "For each additional day that the book is overdue, the total fine is ..."

1st day fine - 0.1
2nd day fine - 0.1*2 = 0.2 (as doubling gives lower value)
3rd day fine - 0.2*2 = 0.4 (as doubling gives lower value)
4th day fine - 0.4 + 0.3 = 0.7 (as doubling gives higher value we add 0.3 this time)

Answer: B.

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by Brent@GMATPrepNow » Tue Jun 11, 2019 8:50 am

rajeet123 wrote: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 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

1st day - $0.10

2nd day - $0.20 or $0.40 (double or add $0.30)
$0.20 is the lesser amount

3rd day - $0.40 or $0.50 (double or add $0.30)
$0.40 is the lesser amount

4th day - $0.80 or $0.70 (double or add $0.30)
$0.70 is the lesser amount

The correct answer is B

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

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Scott@TargetTestPrep: GMAT Instructor; Posts: 8086; Joined: Sat Apr 25, 2015 10:56 am; Location: Los Angeles, CA; Thanked: 43 times; Followed by:29 members

by Scott@TargetTestPrep » Fri Jun 14, 2019 8:35 am

rajeet123 wrote: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 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

On day 1, the fine is $0.10.

On day 2, we have two options:

1) 0.10 + 0.30 = $0.40

2) 0.10 x 2 = $0.20

Since option 2 is the lesser of the 2 fines, the total fine, as of day 2, is $0.20.

On day 3 we have two options:

1) 0.20 + 0.30 = $0.50

2) 0.20 x 2 = $0.40

Since option 2 is the lesser of the 2 fines, the total fine, as of day 3, is $0.40.

On day 4 we have two options:

1) 0.40 + 0.30 = $0.70

2) 0.40 x 2 = $0.80

Since option 1 is the lesser of the 2 fines, the total fine, as of day 4, is $0.70.

Answer: B

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