Given,
Mass of solute = 30 g
Mass of solvent = 300 g
So, Mass of solution = Mass of solute + Mass of solvent
= 30 + 300 = 330 g
Mass by mass percentage of a solution =mass of solutemass of solution×100
On putting values in formula, we get
= (30/330)*100
= 9.09 %
Hence, Peeyush has prepared a solution of concentration 9.09% by mass.