Problem $18-4($Algo$)$

Here are the data for the past $21$ months for actual sales of a particular product:

Develop a forecast for the fourth quarter using a three$-$quarter, weighted moving average. Weight the most recent

quarter $0\mathrm{.}50,$ the second most recent $0\mathrm{.}25,$ and the third $0\mathrm{.}25.$ Do the problem using quarters as opposed to

forecasting separate months.

Note: Round your answer to $2$ decimal places.