Calculate the mass fraction of salt obtained by mixing 60 g of a 4% solution and 80 g of a 6% solution.

Given: m1 = 60g, m2 = 80g, W1 = 4%, W2 = 6%
We will use the formula m (salt) = m (solution) * W (salt) / 100
m1 (salt) = 60 * 4/100 = 2.4 g
m2 (salt) = 80 * 6/100 = 4.8 g
In the general solution, the mass of salts will be:
m3 (salt) = 2.4 + 4.8 = 7.2 g
Solution weight:
m3 = 80 + 60 = 140 g.
W3 = (7.2 / 140) * 100 = 5.14%
Answer: the mass fraction of salt obtained by mixing is 5.14%