Question 422361
I assume 12 dollars means 12 hundred dollars since the value, v, is given in hundreds of dollars.  
If so, then putting the problem into equation form, we have:
{{{v = 12 + (1/3)*t}}}
{{{graph(300,200,-2,10,-2,30,12+x/3)}}}
Debbie's collection is 9 yrs. old so the value is 12+(9/3) = 15*100 = $1500