Last visit was: 19 Nov 2025, 07:59 It is currently 19 Nov 2025, 07:59
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
dabaobao
User avatar
Joined: 24 Oct 2016
Last visit: 20 Jun 2022
Posts: 570
Own Kudos:
1,639
 [10]
Given Kudos: 143
GMAT 1: 670 Q46 V36
GMAT 2: 690 Q47 V38
GMAT 3: 690 Q48 V37
GMAT 4: 710 Q49 V38 (Online)
GMAT 4: 710 Q49 V38 (Online)
Posts: 570
Kudos: 1,639
 [10]
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc Updated on: 30 Mar 2019, 12:02
Originally posted by dabaobao on 30 Mar 2019, 11:50.
Last edited by dabaobao on 30 Mar 2019, 12:02, edited 1 time in total.
Kudos
Add Kudos
10
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

85% (hard)

Question Stats:

54% (02:43) correct 46% (02:32) wrong based on 276 sessions

History

Date
Time
Result
Not Attempted Yet
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calculates the dollar amount of the tip as 3 times the tens digit of the amount of his bill. If the amount of Tom’s most recent cafeteria bill was 2-digit integer, was the tip calculated by Tom on this bill greater than 20 percent of the amount of the bill?

(1) The amount of the bill excluding tip was over $20
(2) The tip calculated by Tom was at least $4
ShowHide Answer
Official Answer
D
User avatar
dabaobao
User avatar
Joined: 24 Oct 2016
Last visit: 20 Jun 2022
Posts: 570
Own Kudos:
1,639
Given Kudos: 143
GMAT 1: 670 Q46 V36
GMAT 2: 690 Q47 V38
GMAT 3: 690 Q48 V37
GMAT 4: 710 Q49 V38 (Online)
GMAT 4: 710 Q49 V38 (Online)
Posts: 570
Kudos: 1,639
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc Updated on: 31 Mar 2020, 05:11
Originally posted by dabaobao on 30 Mar 2019, 12:00.
Last edited by dabaobao on 31 Mar 2020, 05:11, edited 1 time in total.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
dabaobao
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calculates the dollar amount of the tip as 3imes the tens digit of the amount of his bill. If the amount of Tom’s most recent cafeteria bill was 2-digit integer, was the tip calculated by Tom on this bill greater than 20 percent of the amount of the bill?

(1) The amount of the bill excluding tip was over $20
(2) The tip calculated by Tom was at least $4
Show more


Similar to Q: https://gmatclub.com/forum/whenever-mar ... l#p2251680

Q: Actual Tip > 20% of Bill?

Trick: Min/Max



Method 1: Test Cases (Faster)



1) Consider to extremes in 20s
Tip = 6
When bill is 21, 20% Tip = ~$4 => Yes
When bill is 30, 20% Tip = ~$6 => Yes
Sufficient

2) Consider to extremes in 20s
Tip = 6
When bill is 21, 20% Tip = ~$4 => Yes
When bill is 30, 20% Tip = ~$6 => Yes
Sufficient

ANSWER: D


Solution 2: Slower





List the Ranges:
Bill Range: 11-19, 21-29, 31-39, ...
Tip Range: 2<x<4, 4<x<6, ...
Actual Tip: 3, 6, 9, ...

Simplify the Q



Notice, tip > 20% of the bill when:
1) bill > 20
2) tip > $3

Hence the Q is asking:

Is bill > 20 or tip > 3?

1) bill > 20. Sufficient
2) Tip > 4. Sufficient

Hence, answer = D.
avatar
ArupRS
avatar
Joined: 23 Jan 2018
Last visit: 02 Jul 2025
Posts: 254
Own Kudos:
248
Given Kudos: 358
Location: India
Concentration: Technology, General Management
Schools: Goizueta '26 (S) Rotman '24 Mendoza '26 (D) Questrom '26 (A$$)
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q49 V36 (Online)
WE:Information Technology (Computer Software)
Products:
My Reviews
Schools: Goizueta '26 (S) Rotman '24 Mendoza '26 (D) Questrom '26 (A$$)
GMAT 2: 700 Q49 V36 (Online)
Posts: 254
Kudos: 248
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc 15 Jun 2019, 05:43
Kudos
Add Kudos
Bookmarks
Bookmark this Post
chetan2u
Not able to understand what the problem is asking. Could you please explain?

Regards,
Arup
User avatar
chetan2u
User avatar
GMAT Expert
Joined: 02 Aug 2009
Last visit: 15 Nov 2025
Posts: 11,238
Own Kudos:
43,703
 [3]
Given Kudos: 335
Status:Math and DI Expert
Location: India
Concentration: Human Resources, General Management
GMAT Focus 1: 735 Q90 V89 DI81
Products:
My Reviews
Expert
Expert reply
GMAT Focus 1: 735 Q90 V89 DI81
Posts: 11,238
Kudos: 43,703
 [3]
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc 15 Jun 2019, 09:26
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
dabaobao
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calculates the dollar amount of the tip as 3 times the tens digit of the amount of his bill. If the amount of Tom’s most recent cafeteria bill was 2-digit integer, was the tip calculated by Tom on this bill greater than 20 percent of the amount of the bill?

(1) The amount of the bill excluding tip was over $20
(2) The tip calculated by Tom was at least $4
Show more


Hi ArupRS,

Of course, the question is not written properly..
What it says is the bill is a 2-digit amount that is \($10\leq{bill}\leq{$99}\). So, if the amount is a 2-digit number, we can write it as ab or 10a+b..
tip is 3a
So we are asked if tip 3a>20% of (10a+b).....\(3a>\frac{20}{100}(10a+b)...15a>10a+b......5a>b\)...
Now max value of b can be 9, so if we know a is at least 2, 5a>b irrespective of the value of b.

Question becomes - Is 5a>b? .


So, either we require to know the value of both a and b if a is 1, otherwise answer is always YES.

(1) The amount of the bill excluding tip was over $20
So, the tens digit or \(a\geq{2}\).
Suff

(2) The tip calculated by Tom was at least $4
so 3a>4.....\(a>\frac{4}{3}\). Since a is an integer, a will be at least 2.
Again sufficient.

D
avatar
ArupRS
avatar
Joined: 23 Jan 2018
Last visit: 02 Jul 2025
Posts: 254
Own Kudos:
248
Given Kudos: 358
Location: India
Concentration: Technology, General Management
Schools: Goizueta '26 (S) Rotman '24 Mendoza '26 (D) Questrom '26 (A$$)
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q49 V36 (Online)
WE:Information Technology (Computer Software)
Products:
My Reviews
Schools: Goizueta '26 (S) Rotman '24 Mendoza '26 (D) Questrom '26 (A$$)
GMAT 2: 700 Q49 V36 (Online)
Posts: 254
Kudos: 248
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc 15 Jun 2019, 10:47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
chetan2u
dabaobao
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calculates the dollar amount of the tip as 3 times the tens digit of the amount of his bill. If the amount of Tom’s most recent cafeteria bill was 2-digit integer, was the tip calculated by Tom on this bill greater than 20 percent of the amount of the bill?

(1) The amount of the bill excluding tip was over $20
(2) The tip calculated by Tom was at least $4


Hi ArupRS,

Of course, the question is not written properly..
What it says is the bill is a 2-digit amount that is \($10\leq{bill}\leq{$99}\). So, if the amount is a 2-digit number, we can write it as ab or 10a+b..
tip is 3a
So we are asked if tip 3a>20% of (10a+b).....\(3a>\frac{20}{100}(10a+b)...15a>10a+b......5a>b\)...
Now max value of b can be 9, so if we know a is at least 2, 5a>b irrespective of the value of b.

Question becomes - Is 5a>b? .


So, either we require to know the value of both a and b if a is 1, otherwise answer is always YES.

(1) The amount of the bill excluding tip was over $20
So, the tens digit or \(a\geq{2}\).
Suff

(2) The tip calculated by Tom was at least $4
so 3a>4.....\(a>\frac{4}{3}\). Since a is an integer, a will be at least 2.
Again sufficient.

D
Show more

Nice explanation. Thank you so much .

Regards,
Arup Sarkar
User avatar
MSIMBA
User avatar
Joined: 04 Jun 2017
Last visit: 14 Aug 2020
Posts: 73
Own Kudos:
40
Given Kudos: 180
Location: India
Concentration: Strategy, Operations
GMAT 1: 500 Q39 V20
GPA: 3.82
GMAT 1: 500 Q39 V20
Posts: 73
Kudos: 40
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc 15 Jun 2019, 20:25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
gAs given 1. tip is atleast 3 times than ten's digit 2. tip is 20 % of total bill?

1. min bill = 20, as per given items
3 * 2 = 6 min tip , 20 * 20 % = 4

Min tip > 20 % total bil

A sufficient

B. min tip is 4
if we take 19 ,than 1 * 3 = 3 , min bill < 4
take 20 ,than 2 * 3 = 6 min bill 6 (tip)
& 2 0% of 20 = 4 , which is less than 6 (tip)

B sufficient

Both are sufficicent , D is answer
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,588
Own Kudos:
1,079
Posts: 38,588
Kudos: 1,079
Whenever Tom pays an amount of 2-digit integer in a cafeteria, he calc 26 Jan 2025, 11:10
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.
Moderators:
Bunuel
Math Expert
105389 posts
kingbucky
496 posts