Is it true that a b ? (1) 3a 5b (2) –a

Question

Is it true that a > b ?
 
(1) 3a > 5b
(2) –a < –b

0akshay0 · Answer

St I 3a > 5b which means 3a > 4b > 3b therfore 3a > 3b ==> a > b ----------Sufficient St II –a < –b ==> a > b --------Sufficient Hence option D is correct Hit Kudos if you liked it 8-)

mehrotrayashraj · Answer

Statement 1 breaks for a=5, and b=3
Statement 2 when multiplied by -1 gives the answer.

Ans : B

debtanuB · Answer

from (1), its clear that 3a>5b => a>b ,
how come you are saying for a=5 & b=3 the statement breaks down??
if a=5 & b=3, 3*5>5*3 , but both are equal, actually here its already mentioned 3a>5b so you cannot assume their values for which (1) goes wrong,
you are trying to prove 3a>5b wrong on the basis of the main question ,i.e, a>b
the answer should be D.

milano10 · Answer

0akshay0   Lithium 
Note that it is not stated whether a and b are positive numbers. This is one way for gmat to trick you. Don't fall for it and test negative numbers as well.

The correct answer is B and here is why:
1) 3a > 5b --> let's assume a=5; b= 2 --> 15>10 --> a>b stands. 
However, if we assume that a = -3 and b= -2, it goes that -9>-10, but b>a. NOT sufficient.
2) clearly sufficient *-1 both sides and < changes to >

Hope this helped.

amanvermagmat · Answer

Statement 1. 3a > 5b Or a > 5b/3

Now, if b is positive and if a > 5b/3, then definitely a > b
But if b is negative, we cannot be sure.

Eg - lets say b=-3, then a > 5b/3 or a > -5. Here a could be -4, so now while a > 5b/3, a < b.
So Insufficient.

Statement 2. -a < -b
Multiplying both sides by -1, a > b. Sufficient.

Hence B answer

debtanuB · Answer

thnx man...finally got it

arvind910619 · Answer

IMO B ,
 Statement 1 is not sufficient.
Let us take an example :  Suppose a=-1 and b=-1 
Then we have -3 >-5 from statement 1 
 But we took a=b=-1 hence it is not sufficient

origen87 · Answer

We need to disprove a>b with variables.

1. 3a>5b

Now for a>b; a=4,b=2 proves both a>b and 3a>5b

Disproving a>b; a=-3,b=-3 satisfies 3a>5b and disproves a>b. So not sufficient.

B

Is it true that a > b ? (1) 3a > 5b (2) –a < –b

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Data Sufficiency (DS) Questions