Wires W _ 1 and W _ 2 are made of same material having the breaking...

Wires ${W}_{1}$ and ${W}_{2}$ are made of same material having the breaking stress of $1 . 25 \times {10}^{9}N{m}^{- 2} . {W}_{1}$ and ${W}_{2}$ have cross-sectional area of $8 \times {10}^{- 7}{m}^{2} and$4 \times {10}^{- 7}{m}^{2}$, respectively. Masses of$20kg$and$10kghang from them as shown in the figure. The maximum mass that can be placed in the pan without breaking the wires is _____kg$(Use \leftg = 10m{s}^{- 2})$