Last visit was: 11 Jul 2025, 17:46 It is currently 11 Jul 2025, 17:46
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
rheam25
Joined: 17 Jul 2019
Last visit: 24 Apr 2021
Posts: 69
Own Kudos:
613
 [8]
Given Kudos: 296
Posts: 69
Kudos: 613
 [8]
2
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
User avatar
IanStewart
User avatar
GMAT Tutor
Joined: 24 Jun 2008
Last visit: 11 Jul 2025
Posts: 4,141
Own Kudos:
10,611
 [2]
Given Kudos: 97
 Q51  V47
Expert
Expert reply
Posts: 4,141
Kudos: 10,611
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
sujoykrdatta
Joined: 26 Jun 2014
Last visit: 10 Jul 2025
Posts: 539
Own Kudos:
1,039
 [3]
Given Kudos: 13
Status:Mentor & Coach | GMAT Q51 | CAT 99.98
Expert
Expert reply
Posts: 539
Kudos: 1,039
 [3]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Kritisood
Joined: 21 Feb 2017
Last visit: 19 Jul 2023
Posts: 492
Own Kudos:
Given Kudos: 1,090
Location: India
GMAT 1: 700 Q47 V39
Products:
GMAT 1: 700 Q47 V39
Posts: 492
Kudos: 1,217
Kudos
Add Kudos
Bookmarks
Bookmark this Post
IanStewart
rheam25
A bag contains only two types of coins: 10 cent coins or 1 dollar coins and number of 10 cent coins does not exceed the number of 1 dollar coins. How many 10 cent coins are there in the bag?

(1) The total amount of money in the bag is $16.50.

(2) If five 10-cent coins are removed and replaced with five 1-dollar coins then two-third of all the coins in the bag are 1 dollar coins.

We can't have too many ten cent coins, so Statement 1 can only be true for very specific numbers. We might have 16 one-dollar coins and 5 ten-cent coins, or we might have 15 one-dollar coins and 15 ten-cent coins. If we have any fewer one-dollar coins, we'll need to have more ten-cent coins than dollar coins, and that's not allowed. So Statement 1 is almost sufficient, since it leaves us only two possibilities.

Statement 2 is not sufficient since it can be true if we have any odd number of dollar coins. For example, if we have just one dollar coin, and eight dimes, changing five dimes into dollars will make 2/3 of the coins into dollar coins. Or if we have 1001 dollar coins and 508 dimes, again changing five dimes to dollars will make 2/3 of the coins into dollar coins. So Statement 2 is not sufficient.

Using both Statements, Statement 2 rules out one of the two possibilities we had when considering Statement 1, and we must have 15 of each type of coin, so the answer is C.

Hi, I have seen a lot of such GMAT questions where a statement like st 1 is given. On the face value, it seems like it wouldn't be sufficient but upon trial and error, one would realize that only ONE specific set of values would satisfy the equation.
How do you deal with such problems in the exam scenario.. when to know till when do we need to keep checking? (since its a time-consuming process and the correct values don't strike instantly)
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,374
Own Kudos:
Posts: 37,374
Kudos: 1,010
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderator:
Math Expert
102635 posts