Question

Create an odd number that satisfy the following clues
_ Thousand digit is twice ones digit
_ Ten thousand digit is three times the tens digit
_ Each digit is used only once

Answer 1

Thousand digit is twice ones digit: ones digit must be odd
2xx1 , 6xx3 , no others possible

Ten thousand digit is three times the tens digit
2xx1 -----> 92x31, for tens digit, can't use 1,2,4, ..., each digit used only once
6xx3 ---> none possible

92x31 -----> the remaining x could be 0,4,5,7,8,9 ,
e.g. 92731 follows all the given restrictions

How many will there be ?
Can you list them for me?
Did I miss any?

Answer 2

Thdghb