What is the mole fraction of LiCl in a mixture of 0.564g NaCl, 1.52g KCl and 0.857g LiCl?

Molar mass of NaCl = (23.0 + 35.5) g/mol = 58.5 g/mol
Molar mass of KCl = (39.0 + 35.5) g/mol = 74.5 g/mol
Molar mass of LiCl = (6.9 + 35.5) g/mol = 42.4 g/mol

No. of moles of NaCl = (0.564 g) / (58.5 g/mol) = 0.00964 g
No. of moles of KCl = (1.52 g) / (74.5 g/mol) = 0.0204 g
No. of moles of LiCl = (0.857 g) / (42.4 g/mol) = 0.0202 g

Mole fraction of LiCl = 0.00964 / (0.00964 + 0.0204 + 0.202) = 0.192

Atomic weights:
Lithium 6.94; Sodium 22.99, Potassium 39.10, Chlorine 35.45.

(0.857 g)/(42.39 g/mol) = 20.22 mmol;
(0.564 g)/(58.44 g/mol) = 9.651 mmol;
(1.52 g)/(74.55 g/mol) = 20.39 mmol.

The mole fraction of LiCl is
(20.22)/(20.22 + 9.651 + 20.39)
= about 40% but use a calculator