Take a 3 digit number 'abc'. If we add abc, cab and bca together then the resulting sum is divisible by_____.
The numbers can be written as:
abc=100a+10b+c
cab=100c+10a+b
bca=100b+10c+a
Adding all we get;
Sum
=(100a+10a+a)+(100b+10b+b)+(100c+10c+c)
Sum
=111a+111b+111c
Sum
=111(a+b+c)
= 37×3(a+b+c)
∴ the the number will be divisible by 3.