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\begin{aligned} T_{2} &=27.3 \mathrm{~d} \times \dfrac{24.0 \mathrm{~h}}{\mathrm{~d}} \times\left(\dfrac{7880 \mathrm{~km}}{3.84 \times 10^{5} \mathrm{~km}}\right)^{3 / 2} \\ &=1.93 \mathrm{~h} \end{aligned}