Question 828926
A multiple of {{{3}}} would be {{{3x}}} where {{{x}}} is any number. 
The next (consecutive) multiple would be {{{3x+3}}}.
{{{3x+(3x+3)=69}}}
{{{6x+3=69}}}
{{{6x=66}}}
{{{x=11}}}
So the first multiple is {{{3x}}} or {{{33}}} and the second multiple if {{{3x+3}}} or {{{36}}}.