A plane is in level flight at constant speed and each of its two wings has an area of 40 m^2. If the speed of the air is 180 km / h over the lower…

A plane is in level flight at constant speed and each of its two wings has an area of $\displaystyle 40 \mathrm{~m}^2$. If the speed of the air is $\displaystyle 180 \mathrm{~km} / \mathrm{h}$ over the lower wing surface and $\displaystyle 252 \mathrm{~km} / \mathrm{h}$ over the upper wing surface, the mass of the plane is $\displaystyle \_\_\_\_$ kg . (Take air density to be $\displaystyle 1 \mathrm{~kg} \mathrm{~m}^{-3}$ and $\displaystyle \mathrm{g}=10 \mathrm{~ms}^{-2}$ )