How many five-digit numbers of the form ¯32x5y are divisible by 72?
to be divisible by 72, it has to be divisible by 8 and 9. To be divisible by 9, 3 + 2 + x + 5 + y has to be divisible by 9. So, 10+x+y is divisible by 9. Then, x5y has to be divisible by 8. Now, if you list it all out, you should get an answer.
Out of 100 integers of this form, I could find only one such number: 32256 mod 72 =0
Thnaks, Guest!
