Question

287+x and 378+x which can never be its factor 26,13,19,7

Answer 1

Hi friend,
These type of questions we need to solve it by eliminating options so as 26 is divisble by 13 among the two we need to verfiy only one option so when we divide 287 and 378 by 13 we get remainder as 1 there fore we can say that 287+x and 378+x are divisble by 13.So trick is simple divide options with both given numbers if you get same remainder then they can be factors .Even for 7 u get same remainder so 19 can never be factor of 287+x and 378+x as we get different remainder.
 HOPE THIS HELPS....