Wires `W_(1)` and `W _(2)` are made of same material having the breaking stress of `1.25 xx 10 ^(9) N//m ^(2). W _(1) and W _(2)` have cross-sectional area of `8 xx 10 ^(-7) m ^(2) and 4 xx 10 ^(-7) m ^(2),` respectively. Masses of 20 kg and 10 kg hang from them as shown in the figure. The maximum mass that can be placed in the pan without breaking the wires is kg. (Use `g = 10 m//s ^(2)`)