Given the following data, what is the weighted moving average forecast with weights of $\mathrm{.}5,\mathrm{.}3,$ and $\mathrm{.}2$ respectively $($WMA $\mathrm{.}5,3,\mathrm{.}2)$ for period $3?$

Month Demand

$\backslash$table$[[1,19],[2,20],[3,18],[4,19],[5,17]]$

no value

$18\mathrm{.}8$

$17\mathrm{.}8$

$18\mathrm{.}9$