You need to dissolve CaCl2 in water to make a mixture that is 39.0% calcium chloride by mass. If the total mas

You need to dissolve CaCl2 in water to make a mixture that is 39.0% calcium chloride by mass. If the total mass of the mixture is 968.7 g, what masses of CaCl2 and water should be used?

How do you go about solving this question? Not just the answer.

39% by mass CaCl2, like percents,
is 39/100, or 39g CaCl2/ 100g mixture

It's a matter of percents.
100 - 39 = 61% water by mass
968.7g = mass CaCl2 & H2O
968.7g x 39/100 = 377.8g CaCl2
968.7g x 61/100 = 590.9g H2O