If a,b, and c are positive, is ac>5?
1) a+b=3
2) 4=c-b
OA is E
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
number properties ds problem..
This topic has expert replies
-
mitaliisrani
- Senior | Next Rank: 100 Posts
- Posts: 56
- Joined: Sun Mar 21, 2010 11:06 am
-
mohit11
- Master | Next Rank: 500 Posts
- Posts: 293
- Joined: Thu Jan 14, 2010 9:08 am
- Location: India
- Thanked: 36 times
- Followed by:5 members
- GMAT Score:730
If a,b, and c are positive, is ac>5?
1) a+b=3
2) 4=c-b
1. a + b = 3 , possible combinations:
(0.5 2.5) (1, 2) (2,1) --- (0,3) and (3,0) is ruled out because 0 is neither positive nor negative.
This statement does not say anything about c so ruled out
ac could be less than 5(1*2) or could be greater than 5 (1*6 )
2. c - b = 4
This statement is useless because all it tells us is that c is 4 ahead of b on the number line.
c,b could be 60, 56 or 3.99, 0.1
We are not told anything about A so Eliminate.
Combined.
a+b = 3
c-b = 4
add them
a + c = 7
minimum value of a or c could be 1, and if a is 1 can has to be 6 to satisfy the equation and ac would be greater than 5
but if a is 0.5 and b is 6.5 then ac would be 3.25, which is less than 5
Hence even together both equations do not help us in answering the question.
1) a+b=3
2) 4=c-b
1. a + b = 3 , possible combinations:
(0.5 2.5) (1, 2) (2,1) --- (0,3) and (3,0) is ruled out because 0 is neither positive nor negative.
This statement does not say anything about c so ruled out
ac could be less than 5(1*2) or could be greater than 5 (1*6 )
2. c - b = 4
This statement is useless because all it tells us is that c is 4 ahead of b on the number line.
c,b could be 60, 56 or 3.99, 0.1
We are not told anything about A so Eliminate.
Combined.
a+b = 3
c-b = 4
add them
a + c = 7
minimum value of a or c could be 1, and if a is 1 can has to be 6 to satisfy the equation and ac would be greater than 5
but if a is 0.5 and b is 6.5 then ac would be 3.25, which is less than 5
Hence even together both equations do not help us in answering the question.
Founder of Consulting Network: https://consultingnetwork.co.in - A portal for consultants
Facebook Page for Consulting Network: https://www.facebook.com/globalconsultingnetwork
My Blog: https://outspoken-mind.blocked
730 Debrief: https://www.beatthegmat.com/730-q49-v41- ... 80010.html
Facebook Page for Consulting Network: https://www.facebook.com/globalconsultingnetwork
My Blog: https://outspoken-mind.blocked
730 Debrief: https://www.beatthegmat.com/730-q49-v41- ... 80010.html
at the first glance it's easy to see that the answer can be only C or E
statement 1) does not give us information about "c"
statement 2) does not give us information about "a"
regarding option C , dear mohit11 give an explanation why it cannot be C. so, only E remains.
statement 1) does not give us information about "c"
statement 2) does not give us information about "a"
regarding option C , dear mohit11 give an explanation why it cannot be C. so, only E remains.
-
gmatmachoman
- Legendary Member
- Posts: 2326
- Joined: Mon Jul 28, 2008 3:54 am
- Thanked: 173 times
- Followed by:2 members
- GMAT Score:710
@blaster ,blaster wrote:at the first glance it's easy to see that the answer can be only C or E
statement 1) does not give us information about "c"
statement 2) does not give us information about "a"
regarding option C , dear mohit11 give an explanation why it cannot be C. so, only E remains.
Case 1 :
C= 4.1
a= 2.1
AC is greater than 5
case 2 :
C= 4.1
a= 0.1
AC is less than 5
So that makes sense why Mohit picked E
