The weights are $\mathrm{.}20,\mathrm{.}30,\mathrm{.}50($oldest period to most recent period$)$

Week

$1$

$2$

$3$

$4$

Time Series Value

$18\mathrm{.}00$

$21\mathrm{.}00$

$18\mathrm{.}09$

$20\mathrm{.}00$

Submit

Answer format: Number: Round to: $1$ decimal places