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Q.)One litre of water is evaporated from 6 litres of a solution containing 5% salt. The percetange of salt in the remaining solution is

1)$ 4\frac { 4 }{ 9 } $ %

2) $ 5\frac { 5 }{ 7 } $ %

3) 5%

4) 6%

Solution :

Salt present in 6 litres = $\frac { 6*5 }{ 100 } $ = 0.3 litre

Water present in 6 litres = 6 – 0.3 = 5.7 litres

1 litre of water evaporated. Hence , remaining water = 5.7 – 1 = 4.7 litres

Percentage of Salt in the remaining Solution = $\frac { 0.3 }{ (0.3+4.7) } X100=\frac { 0.3 }{ 5 } X100=6 $ %

Henc , Option(4)