Explanation
Correct answer: B.
Choice B is correct. It’s given that a chemist mixes kilograms of a low-salt mixture, which is salt by weight. Multiplying by the amount of the low-salt mixture, kilograms, yields kilograms of salt in the low-salt mixture. It's also given that the chemist mixes kilograms of a high-salt mixture, which is salt by weight. Multiplying by the amount of the high-salt mixture, kilograms, yields kilograms of salt in the high-salt mixture. Therefore, the total amount of salt in the combined mixture is kilograms. It's given that the low-salt mixture and the high-salt mixture together create kilograms of a combined mixture that is salt by weight. Thus, the amount of salt in the combined mixture is kilograms. Since the total amount of salt in the combined mixture equals the amount of salt in the low-salt mixture and the amount of salt in the high-salt mixture, the equation represents this situation.
Desmos solution:
Note: The first equation represents the total salt from both mixtures, and the second represents the total weight.
Enter in Desmos:
Reviewed and rewritten by CookSAT
Why the other choices are wrong
Choice A
Choice A is incorrect. This equation represents a situation where the low-salt mixture is , not , salt by weight and the high-salt mixture is , not , salt by weight.
Choice C
Choice C is incorrect. This equation represents a situation where the low-salt mixture is , not , salt by weight and the high-salt mixture is , not , salt by weight, and where the combined mixture contains kilograms of salt, not kilograms of a mixture that is salt by weight.
Choice D
Choice D is incorrect. This equation represents a situation where the combined mixture contains kilograms of salt, not kilograms of a mixture that is salt by weight.