Well Hydraulics and Groundwater

A fully penetrating well in a confined aquifer of thickness $b = 10\text{ m}$ is pumped at steady rate $Q = 0.05\text{ m}^3/\text{s}$. Two observation wells at radial distances $r_1 = 20\text{ m}$ and $r_2 = 100\text{ m}$ show drawdowns $s_1 = 3.0\text{ m}$ and $s_2 = 1.0\text{ m}$, respectively (so $s_1 - s_2 = 2.0\text{ m}$). With $\ln(5) = 1.609$, the transmissivity $T$ of the aquifer in m$^2$/s is: