GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Nov 2018, 09:50

### 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

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

## Events & Promotions

###### Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• ### How to QUICKLY Solve GMAT Questions - GMAT Club Chat

November 20, 2018

November 20, 2018

09:00 AM PST

10:00 AM PST

The reward for signing up with the registration form and attending the chat is: 6 free examPAL quizzes to practice your new skills after the chat.
• ### The winning strategy for 700+ on the GMAT

November 20, 2018

November 20, 2018

06:00 PM EST

07:00 PM EST

What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.

# If a, b, x, y, and z are non negative integers and [m]2^a — 2^b = (3^x

Author Message
TAGS:

### Hide Tags

Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1033
Location: India
GPA: 3.64
WE: Business Development (Energy and Utilities)
If a, b, x, y, and z are non negative integers and [m]2^a — 2^b = (3^x  [#permalink]

### Show Tags

27 Oct 2018, 09:05
1
00:00

Difficulty:

45% (medium)

Question Stats:

70% (01:15) correct 30% (02:09) wrong based on 22 sessions

### HideShow timer Statistics

If a, b, x, y, and z are non negative integers and $$2^a — 2^b = (3^x)(2^y)(7^Z)$$. what is the value of xyz?
1) a-b=3
2) yz > O

Weekly Quant Quiz #6 Question No 2

_________________
Intern
Joined: 09 May 2017
Posts: 4
Re: If a, b, x, y, and z are non negative integers and [m]2^a — 2^b = (3^x  [#permalink]

### Show Tags

27 Oct 2018, 09:35
Ans: A
Since all are non-negative numbers, a>b. Which makes the question--2^b * (2^(a-b) – 1) = 3^x * 2^y * 7^z

Let us consider Statement 1:
a-b=3
Substituting gives us-> 2^b * (2^3 - 1) = 2^b * 7
So we get x=0, y=b and z=1, which gives xyz = 0.
Thus statement 1 is sufficient.

Now statement 2:
yz>0
This statement tells us that y and z both are not zero, but it tells us nothing about x.
If a-b=3, we get x=0 and thus xyz = 0.
But if a-b=6, we get x=2, y=b and z=1. Since we do not know b, we can not calculate the value of xyz.
Thus, Statement 2 is insufficient.

##### General Discussion
Manager
Joined: 12 Mar 2018
Posts: 50
GMAT 1: 640 Q49 V29
GPA: 4
Re: If a, b, x, y, and z are non negative integers and [m]2^a — 2^b = (3^x  [#permalink]

### Show Tags

27 Oct 2018, 09:29
a-b = 3 is insufficient
yz>0 is insufficient since there is no information about x.

2^a-2^b = 2^b(2^a-b - 1) = 2^b * 7^1 ; x=0, z= 1, y=b...
IMO
E?
Re: If a, b, x, y, and z are non negative integers and [m]2^a — 2^b = (3^x &nbs [#permalink] 27 Oct 2018, 09:29
Display posts from previous: Sort by