number properties ds problem..

[mitaliisrani]

If a,b, and c are positive, is ac>5?
1) a+b=3
2) 4=c-b

OA is E

[mohit11]

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.

[blaster]

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.

[gmatmachoman]

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.

@blaster ,

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

[ckjakky]

both a and c positive?
cos you can have multiple anwsers with a=8,c=-1