Math problems from the *free* official practice tests and
problems from mba.com
viveksharma247
Students
 
Posts: 5
Joined: Sat May 31, 2008 10:53 am
 

If a, b, and c are integers, what is the value of a?

by viveksharma247 Sun Sep 06, 2009 10:58 am

Seeking for some help to solve this GMAT prep DS problem:

If a, b, and c are integers, what is the value of a?

(i) (a-7)(b-7)(c-7) = 0
(ii) bc = 18

The answer as per GMAT prep is C.
Kweku.Amoako
 
Posts: 47
Joined: Thu Nov 06, 2008 4:13 am
 

Re: If a, b, and c are integers, what is the value of a?

by Kweku.Amoako Sun Sep 06, 2009 11:47 am

1) if (a-7)(b-7)(c-7) = 0 and a,b,c are all integers then either (a-7) = 0 in which case a= 7 or (b-7)= 0 in which case b = 7 or (c-7) = 0 in which case c = 7. Not sufficient

2) ab = 7 says nothing about A so Insufficient

3) If a,b or c must be 7 and we know bc = 18(which is not multile of 7) then we know neither b nor c is equal 7 so a must be 7. Sufficient
viveksharma247
Students
 
Posts: 5
Joined: Sat May 31, 2008 10:53 am
 

Re: If a, b, and c are integers, what is the value of a?

by viveksharma247 Sun Sep 06, 2009 12:19 pm

Thanks! I assumed that a=7 from (i). Thus, (ii) wasn't making any sense to me! Thanks for the great explanation.
RonPurewal
Students
 
Posts: 19744
Joined: Tue Aug 14, 2007 8:23 am
 

Re: If a, b, and c are integers, what is the value of a?

by RonPurewal Fri Sep 25, 2009 11:44 pm

Kweku.Amoako Wrote:1) if (a-7)(b-7)(c-7) = 0 and a,b,c are all integers then either (a-7) = 0 in which case a= 7 or (b-7)= 0 in which case b = 7 or (c-7) = 0 in which case c = 7. Not sufficient

2) ab = 7 says nothing about A so Insufficient

3) If a,b or c must be 7 and we know bc = 18(which is not multile of 7) then we know neither b nor c is equal 7 so a must be 7. Sufficient


excellent.