Question

a,b and c separately can do a piece of work in 15 days b alone can do it in 30 days and c can do it alone in 40 days in how many days a can do the piece of work
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Answer 1

Answer:

The process of deriving large crystals of pure substances from their solutions is known as crystallisation. It is a physical change. Crystals of salt are obtained by the evaporation of sea water. ... This mixture when filtered and allowed to cool produces crystals of copper sulphate.