The mass fraction of potassium nitrate in a solution obtained by evaporation of 150 g

The mass fraction of potassium nitrate in a solution obtained by evaporation of 150 g of water from 800 g of a 30% potassium nitrate solution is equal to:

Given:
m (H2O) = 150 g
m solution 1 (KNO3) = 800 g
w1 (KNO3) = 30% = 0.3
To find:
Let w1 (KNO3) – x
m solution 2 (KNO3) = 800 g-150 g = 650 g
m in-va 1 (KNO3) = m in-va 2 (KNO3)
800 g * 0.3 = x * 650 g
240g = x * 650g
x = 0.3692 * 100%
x = 36.92%
Answer: 36.92%