Question

Using divisibility test, determine $70169308$ is divisible by $11$.

Answer 1

The rule for the divisibility of $11$ states that if the difference between the sums of the alternate digits of the given number is either 0 or divisible by $11$, then the number is divisible by $11$.
The sum of alternative digit in $70169308$ are $7+1+9+0=17$ and $0+6+3+8=17$
The difference between two are: $17-17=0$
Hence, $70169308$ is divisible by $11$.