6.7 g of LiNO3 from a 20 %(m/m) LiNO3 solution.
20%(m/m)20 g LiNO₃------------- 100 g solution6.7 g LiNO₃ ------------ ?m = 6.7 * 100 / 20m = 670 / 20m = 33.5 g hope this helps!