apollo168 wrote:

Hi Jay,

Let say these are the given

What is the remainder when x is divided by 7

1) When x is divided by 5 the remainder is 3

2) When x is divided by 6 the remainder is 1

I want to do it using equations since ive realize that during the gmat sometimes plugging in values can be time consuming

so from number 1 x=5a+3

from number 2 we have x= 6b+1

from there how do you arrive at a conclusion?

I think in some situations you have to plug in numbers.

Using your equations..... find two or three values of x and divide by 7.

Clearly both are Insuff.

1) x = 18 or 23

when 18 , 18/7 remainder = 4

When 23, 23/7 remainder = 3

2) x = 7 or 13

when 7, 7/7 remainder = 0

when 13, 13/7 remainder = 6

Together.

x = 13 (13/5 = 3 and 13/6 = 1)

When divided by 7 remainder = 6

x= 43 (43/5 =3 and 43/6 = 1)

When divided by 7 remainder = 1

Hence not suff. The answer would be E