If 5a 6b, is a greater than zero?

Question

If 5a > 6b, is a greater than zero?

(1) a > b
(2) 4b – 5a = 24

Balajikarthick1990 · Answer

It was tough for me...got confused in the middle ...can u pls explain?

chetan2u · Answer

Hi, it is slightly tough 5a>6b... (1) a > b a=8, and b=4.. satisfies both equation and a>0 a=-2, and b=-3.. again satisfies both equation and a<0.. so different answers Insuff (2) 4b – 5a = 24 now 5a>6b or 6b-5a<0.. OR 2b+4b-5a <0.. we know from this statement that 4b-5a = 24, substitute this value in 2b+4b-5a<0. SO 2b+24<0..or 2b<-24 and b<-12.. Now initial equation is 4b-5a=24 , 5a = 4b-24...lets take max value as b=-12 although it is even <-12 5a= 4*-12 -24 =-48-24=-72 so a<0 Suff B

Mo2men · Answer

Hi,
Thank for your help

I do not understand how a<-48

if, for example, a=-50 & b=-15 which invalidates the condition that 5a>6b

If 2b<-24...... b<-12, if substitute in 5a>6b.........5a> 6 (-12) then a can take any value -ve or 0 or+ve

Do I miss something?

chetan2u · Answer

Hi,
there was a typo in solution..
now b<-12..
statement II says 4b-5a = 24..
so 5a = 4b-24..
if b <-12, 4b will also be -ive and it is added to another -ive number -24 so 5a will be -ive and hence a<0..
try with max value, although slightly more than -12, so b=-12..
5a = 4*-12-24=-72. ... so MAX value of a is -72 HENCE a<0..
suff

Hope it helps

Jaidude · Answer

4b - 5a = 24

we can get 4b-24=5a.---(i) since 5a>6b
we can write 4b-24>6b

4b-24>6b

-2b>24

b<-12
so then

4<-48 and 4b-24<-72
from(i) 5a=4b-24
so 5a<-72
hence a<-72/5

since a is less than a negative number , statement 2 is sufficeint.

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If 5a > 6b, is a greater than zero?

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