Q$13.$ Two groundwater wells are pumping from a confined aquifer near an observation well. When only pumping well $1$ is operating, the steady$-$state drawdown at the observation well is $0\mathrm{.}28$ m when the pumping rate is $1\mathrm{.}4$ ML$/$d$.$ When only pumping well $2$ is operating, the steady$-$state drawdown at the observation well is $1\mathrm{.}25$ m when the pumping rate is $0\mathrm{.}5$ ML$/$d$.$ What is the steady$-$state drawdown in metres at the observation well when pumping well $1$ is pumping at $1\mathrm{.}9$ ML$/$d and, simultaneously, pumping well $2$ is pumping at $2\mathrm{.}4$ ML$/$d$?$