Question

For what value of digit x, is :

$1x5\text{divisible by 3 ?}$

Answer 1

$\because 1x5\text{is divisible by 3}\Rightarrow 1+x+5\text{is a multiple of 3}\Rightarrow 6+x=0,3,6,9,.....\Rightarrow x=-6,-3,0,3,6,9\text{Since, x is a digit}\therefore x=0,3,6or9$