Hey!

ill provide the below. please try to understand it

2.45 kg = 2.45 kg.
mass of solute= 50gm
mass of solvent=2.45 kg
mass of solution = 2450+50 = 2500 gm = 2.5 kg

percentage concentration of the solution =
mass of solvent / mass of solution * 100
= 50/2500*100
= 50
Concentration of solution is 50%.

Hope it helps.