Question 52408
Directly Proportional means that 
WHEN revenue for sandwich shop rises,advertising buget ALSO rises

Let S = sandwich shop revenue
Let B = advertising budget

Relationship of S and B are directly proportional.. think {{{(x/y)=k}}}
so {{{(B/S)=k}}}, where k is a constant number that NEVER changes

For the first time, $2,000 on advertising budget nets us $120,000
{{{(2000/120000)=k}}} -> {{{k=(1/6)}}}

Then if the revenue is now $180,000
Solving for B gives us {{{B=S*k}}} -> {{{B=180000*(1/6)}}} 
{{{B=3000}}}