Initial weight , x = 6g
Final weight , y = 10.5 g
Mass percentage of water absorbed = Finalweight−InitialweightInitialweight×100
Mass percentage of water absorbed = y-x/x×100
=10.5 -6 /6 ×100 =4.5/6 ×100 =3/4 ×100 =75 percent .
Raisins swell because up because they have semi permeable membrane and they take up water due to osmosis. Hope this helps