Question 105134
If one number is twice another number, we can first number write as an {{{x}}}, and second number as an {{{2x}}}.
If the sum of the two numbers is {{{39}}}, we can write it:


{{{x + 2x = 39}}}

{{{3x = 39}}}

{{{x = 39/3}}}

{{{x = 13}}} this would be first number

{{{2x = 13*2}}}

{{{2x = 26}}} this would be second number

their sum:

{{{13 + 26 = 39}}}

{{{39 = 39}}}