|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
21 Apr 2021, 02:30
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
76% (01:15) correct
24%
(01:10)
wrong
based on 51
sessions
History
Date
Time
Result
Not Attempted Yet
If x and y are positive integers, is xy a multiple of 18?
(1) x is a multiple of 9.
(2) y is a multiple of x.
(1) x is a multiple of 9.
(2) y is a multiple of x.
21 Apr 2021, 05:06
Kudos
Bookmarks
Solution:
Is xy a multiple of 18 ?where ‘x’ and ‘y’ are positive integers.
=> Is xy = 18n ?where ‘n’ must be an integer
St(1):- x is a multiple of 9
=> x = 9a ; where a is any integer
If a=5 then 9*5 =45 is NOT a multiple of 18 (No)
If a=4 then 9*4 = 36 is a Multiple of 18 (Yes) (Insufficient)
St(2):-y is a multiple of x
=> y = x b ; where b is any integer
If x=9 and y=18, then y=18=2*9=2x (y is a multiple of x) and
xy=9*18, which is a multiple of 18, (Yes).
If x=y=9, then y=9=1*9=x (y is a multiple of x) and
xy=9*9=81, which is not a multiple of 18(No) (Insufficient)
.
Both conditions combined we have,
x is a multiple of 9
y is a multiple of x
Recycling the same values used above,
If x=9 and y=18, then y=18=2*9=2x (y is a multiple of x) and
xy=9*18, which is a multiple of 18, (Yes).
If x=y=9, then y=9=1*9=x (y is a multiple of x) and
xy=9*9=81, which is not a multiple of 18(No) (Insufficient)
(option e)
Devmitra Sen
GMAT SME
Is xy a multiple of 18 ?where ‘x’ and ‘y’ are positive integers.
=> Is xy = 18n ?where ‘n’ must be an integer
St(1):- x is a multiple of 9
=> x = 9a ; where a is any integer
If a=5 then 9*5 =45 is NOT a multiple of 18 (No)
If a=4 then 9*4 = 36 is a Multiple of 18 (Yes) (Insufficient)
St(2):-y is a multiple of x
=> y = x b ; where b is any integer
If x=9 and y=18, then y=18=2*9=2x (y is a multiple of x) and
xy=9*18, which is a multiple of 18, (Yes).
If x=y=9, then y=9=1*9=x (y is a multiple of x) and
xy=9*9=81, which is not a multiple of 18(No) (Insufficient)
.
Both conditions combined we have,
x is a multiple of 9
y is a multiple of x
Recycling the same values used above,
If x=9 and y=18, then y=18=2*9=2x (y is a multiple of x) and
xy=9*18, which is a multiple of 18, (Yes).
If x=y=9, then y=9=1*9=x (y is a multiple of x) and
xy=9*9=81, which is not a multiple of 18(No) (Insufficient)
(option e)
Devmitra Sen
GMAT SME
Moderators:
