the tens digit of a number is twice the ones digit. The sum of the digits in the number is 12. what is the number?

theres many ways to do this. This is one of them

the sum of a two-digit number is 12 that is

39..... 3+9=12

then you reverse 39 so you get 93 (new number formed)

93......9+3=12

then 

12 less than twice the original # (original number is 39)

2(39)-12=

78-12=

66

so your new number formed is 66 

6+6= 12