Question

. By using the divisibility test , find if the 308 is divisible by 11.

Answer 1

Answer:

SOLUTION: divisibility by 11: if the difference between the sum of the digits at odd places and the sum of digits on even places of the number is either 0 or 11 it is divisible by 11

i) 5445

the sum of the odd places 5+4=9

the sum of the even places 4+5=9

9-9=0

since the difference between the sum of the odd places and the sum of even places is 0

it is divisible by 11.

ii) 10824

the sum of the odd places 1+8+4=13

the sum of the even places 0+2=2

13-2=11

since the difference between the sum of the odd places and the sum of even places is 11

it is divisible by 11.

iii) 7138965

the sum of the odd places 7+3+9+5=24

the sum of the even places 1+8+6=15

24-15=9

since the difference between the sum of the odd places and the sum of even places is 19

it is not divisible by 11.

iv) 70169308

the sum of the odd places 7+1+9+0=17

the sum of the even places 0+6+3+8=17

17-17=0

since the difference between the sum of the odd places and the sum of even places is 0

it is divisible by 11.

v) 10000001

the sum of the odd places 1+0+0+0=1

the sum of the even places 0+0+0+1=1

1-1=0

since the difference between the sum of the odd places and the sum of even places is 0

it is divisible by 11.

vi) 901153

the sum of the odd places 9+1+5=15

the sum of the even places 0+1+3=4

15-4=11

since the difference between the sum of the odd places and the sum of even places is 11

it is divisible by 11.