rajnisht wrote:

If |a-b|=c ,what is the value of a?

1. b=2

2.c=7

I know this is not a very difficult problem, but i am bit confused. I think with either of the options we can get the solution.

from 1. we get a-b= c or a-b= -c i.e 2 equations with two unknowns since b is known from this statement.

from 2 .we again get 2 equation with 2 unknowns.

Correct ans is E. Pls guide me how to go for this king of absolute DS.

Hiii,

This is a very simple problem if you grasp the modulus concept on GMAT.

The be low is my approcah for any modulus qtn in GMAT.

Modulus concept:

The meaning of |x-y| is "On the number line, the distance between X and +Y"

The meaning of |x+y| is "On the number line, the distance between X and -Y"

The meaning of |x| is "On the number line, the distance between X and 0".

On the # line, Left to 0 are all the -ve #s and right to 0 are all +ve #s

E.g:

|x-3|=2 ==> distand between x and 3 is 2

==> i can have a # 2 units away to the left of three and also to the right of 3 on the # line

==> x could be 1 (2 units aways from 3 to the left) or 5 (2 units aways from 3 to the right)

Original qtn:

if |a-b|=c ,what is the value of a?

1. b=2

2.c=7

qtn says, on the # line, the distance between a and B is c.

what is the value of a?

stmnt1:

b = 2

the distance between a and 2 is c.....no luck

stmnt2:

the distance between a and B is 7

==> i have a 7 units line connected between a and b

==> no fixed value for a and b as i can move this line along the #,line keeping the distance constant i.e.7

no luck..Not suff.

1&2 together:

the distance between a and 2 is 7

==> |a-2|=7

==> a could be 9 or -5

Not suff.

Hence Answer "E".

Regards,

Murali.

Kudos?