Final answer:
After adding 3 qt of pure antifreeze to 9 qt of a 40% antifreeze solution, the total volume of antifreeze becomes 6.6 qt in a 12 qt solution, leading to a concentration of 55%. The provided answer options do not include this correct answer.
Step-by-step explanation:
The student has asked what the concentration of antifreeze would be in a new solution when 3 qt of antifreeze are added to 9 qt of a 40% antifreeze solution. To solve this problem, one must calculate the total amount of antifreeze before and after the addition of the pure antifreeze.
Initially, there are 9 qt of a 40% solution, which means there are 9 qt x 0.40 = 3.6 qt of antifreeze in the original solution. After adding 3 qt of pure antifreeze, the total amount of antifreeze becomes 3.6 qt + 3 qt = 6.6 qt of antifreeze.
The total volume of the new solution is the original 9 qt plus the 3 qt of antifreeze added, giving us 9 qt + 3 qt = 12 qt of solution. So, the concentration of antifreeze in the new solution is (6.6 qt / 12 qt) x 100%, which equals 55%.
However, none of the provided options match this result. It is important to inform the student about this discrepancy and advise them to double-check the question or the provided answer options.