Test the pisibility of the following numbers by $11$:
a. $7169803$
b. $901351$
c. $818950$

Given: Numbers: a. $7169803$   b. $901351$   c. $818950$

To do: To test the divisibility of the given numbers by $11$.

Solution:

If the difference of the sum of its digits at odd places and sum of its digits at even places is either $0$ or multiple of $11$ then the given number is divisible by $11$.

a. $7169803$

Sum of the digits at odd $=7+6+8+3=24$

Sum of the digit at even place$=1+9+0=10$

Difference between the sums$=10-24=-14$

$-14$ is not divisible by $11$

Thus, $7169803$ is not divisible by $11$.

b. $901351$

Sum of the digits at odd places $=0+3+1=4$

Sum of the digits at even places $=9+1+5=15$

Difference of the two sums$=4-15=-11$

Thus, $901351$ is divisible by $11$.

c. $818950$

Sum of the digits at odd places $=1+3+0=4$

Sum of the digits at even places $=5+1+9=15$

Difference of the two sums$=15-4=11$

Thus, $901351$ is divisible by $11$.