The following regression model has been proposed to predict sales at a computer store. Y hat = 50-3(x1)+20(x2)+10(x3) where x1 = competitors previous day's sales (in $1,000s) and x2 = population within 1 mile (in 1,000s). Predict sales (in dollars) for a store with the competitor's previous day's sale of $5,000, a population of 20,000 within 1 mile, and nine radio advertisements