Historical demand for a product is:

$\backslash$table$[[,$Demand$],[$January$,12],[$February$,11],[$March$,15],[$April$,12],[$May$,16],[$June$,15]]$

a$)$ Using a weighted moving average with weights of $0\mathrm{.}60,0\mathrm{.}30,$ and $0\mathrm{.}10,$ find the July forecast. $($Just use Excel$)$

b$)$ Using a simple three$-$month moving average, find the July forecast.