Final answer:
The percentage of students who walk to school and either bring their lunches or purchase their lunches at school cannot be determined.
Step-by-step explanation:
To find the percentage of students who walk to school and either bring their lunches or purchase their lunches at school, we need to find the intersection between the two groups. Let x be the percentage of students who walk to school and y be the percentage of students who bring their lunches or purchase their lunches at school.
From the given information, we know that x = 65% and y = 75% of x. Therefore, the percentage of students who walk to school and either bring their lunches or purchase their lunches at school is x * y = 65% * 75% = 48.75%. Rounding to the nearest whole number, the answer is 49%, which is not among the options given. Therefore, the correct answer would be D) Cannot be determined.