The tables below show results from a $1-$week monitoring of waste generation rate of three houses in a community. Calculate the average waste generation rate of the houses.

NB: Household sizes of the three households I, $2$ and $3$ are $15,17$ and $18$ respectively.

$\backslash$table$[[,$Days,$1,2,3,4,5,6,7],[$HOUSE I,Waste generated $($kg$/$day$),3\mathrm{.}8,7\mathrm{.}2,4\mathrm{.}5,9\mathrm{.}2,5\mathrm{.}6,10\mathrm{.}1,7\mathrm{.}5],[$HOUSE $2,$Waste generated $($kg$/$day$),5\mathrm{.}1,7\mathrm{.}2,6\mathrm{.}3,7\mathrm{.}5,8\mathrm{.}3,10\mathrm{.}1,14\mathrm{.}3],[$HOUSE $3,$Waste generated $($kg$/$day$),7\mathrm{.}2,4\mathrm{.}8,6\mathrm{.}4,7\mathrm{.}6,8\mathrm{.}5,12\mathrm{.}1,7\mathrm{.}5]]$