The number, $N$ (in million) of VCR's sold in the United States for the years 1990 to 2001 may be approximated by the formula $N=(12 t+1) /(t+2)$, where $t$ is the time in years, with 1990 being $t=0 .$ (a) Find the number sold in $1990,1994,$ and $2000 .$ (b) Find the rate of change of sales in 1990,1994, and 2000.