Last visit was: 21 Apr 2026, 05:16 It is currently 21 Apr 2026, 05:16
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,720
Own Kudos:
Given Kudos: 105,796
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,720
Kudos: 810,375
 [26]
Kudos
Add Kudos
26
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
andreagonzalez2k
Joined: 15 Feb 2021
Last visit: 26 Jul 2025
Posts: 308
Own Kudos:
503
 [9]
Given Kudos: 14
Posts: 308
Kudos: 503
 [9]
7
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
avatar
SirJeepsALot
Joined: 03 Mar 2021
Last visit: 06 Jul 2021
Posts: 8
Own Kudos:
20
 [6]
Given Kudos: 1
Location: India
GMAT 1: 670 Q49 V32
GMAT 1: 670 Q49 V32
Posts: 8
Kudos: 20
 [6]
5
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
General Discussion
avatar
priyanka9601
Joined: 08 Oct 2018
Last visit: 05 Sep 2023
Posts: 2
Own Kudos:
Given Kudos: 15
Location: India
Schools: Haas '24
Schools: Haas '24
Posts: 2
Kudos: 1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Parikshit invests Rs. 1546 in BNP bank at a certain rate of compound interest per annum. At the end of 8 years, he finds that his money has doubled. What approximately is the rate of interest BNP bank paid him?

(A) 9%
(B) 12%
(C) 15%
(D) 16%
(E) 18%

How to you solve the calculation fast?
User avatar
RS81
Joined: 06 Nov 2012
Last visit: 05 Dec 2022
Posts: 36
Own Kudos:
20
 [5]
Given Kudos: 105
Location: United States
Schools: IIMA PGPX "21
WE:Information Technology (Computer Software)
Schools: IIMA PGPX "21
Posts: 36
Kudos: 20
 [5]
1
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
For compound interest any investment doubles in 72yrs at the rate of 1%
If the rate of interest is 10% then number of yrs it will take to double = 72/10 = 7.2yrs

Time is given and rate of interest you need to find
Let the rate of interest be x%
72/x = 8
x=9
Answer = 9yrs

Note = Above is applicable only on the case of amount is double that of principle
User avatar
DonBosco7
Joined: 03 Mar 2020
Last visit: 01 Apr 2026
Posts: 83
Own Kudos:
Given Kudos: 84
Posts: 83
Kudos: 20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
This is more of approximation problem.

Given amount doubles in 8 years
double of 1546 = 3092
A = P(1+r%)^8
3092 = 1546(1+r%)^8
2 = (1+r%)^8
take 8th root............ i know this is scary, but wait...
2^1/8 = 1+r%
Now approximate........... we know 8th root of 1 will be 1, so the 8th root of 2 will be just a little more than 1 say 1.09 (as taken from option choices)

1.09 * 100 = 100 + r
109 - 100 = r
r = 9

Option A
Moderators:
Math Expert
109720 posts
Tuck School Moderator
853 posts