Question

Without actual division show that 15 is a factor of 151230

Answer 1

For proving the no. is divisible by 15. we have to show that 151230 is divisible by 3 as well as 5.
We know that if the sum of all the digit of a no. is divisible by 3, then the no also divisible by 3 and if the last digit of a no. is 0 or 5 then it is divisible by 5. So, 1+5+1+2+3+0=12 (it is divisible by 3). So, 151230 is divisible by 3.
Then, the last digit of 151230 is 0. So, it is divisible by 5.
Hence, 151230 is divisible by 15.

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