Question

Find a and b so that the odd number ababab is divisible by both 3 and 5.

Answer 1

Hi ,

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By Divisibility Conditions:

i ) A natural number is divisible by 3

if and only if sum of it's digits is

divisible by 3 .

ii ) A natural number N divisible by

5 if and only if the digit in it's unit

place is either 0 or 5 .

But according to the problem given ,

We need odd number so the unit

place digit must be 5 .

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Now ,

the required odd number

ababab must be like this ,

a = 1 to 9 , b = 5

Example :

1515151 ,

252525,

353535 ,

454545 ,

555555 ,

656565 ,

757575 ,

858585 ,

959595 ,

I hope this helps you.

: )