An investment manager uses the following formula to predict the value, V, of his investment in dollars, n years after he purchases a new technology stock.
V=68,000+1200(n-3)
Based on this formula, how many years will it take for the investment to best be worth $73,400?
V=73400=68000+1200(n-3)
5400=1200(n-3)=1200(9/2)
so n=3+9/2=$\boxed{15/2 \ years}$