Final answer:
Marshall drove approximately 324 miles in September, as 217 miles driven in October were 67% of the distance he drove in the previous month. To arrive at this conclusion, a proportion was used, and the value was calculated as 217 divided by 0.67.
Step-by-step explanation:
The student has asked how far Marshall drove in September if he drove 217 miles in October, which was 67% of September's distance.
To find the total distance Marshall drove in September, we need to set up a proportion because 67% represents a part of the total distance.
The proportion can be represented as:
67% (the percentage) / 100 = 217 miles (the part) / X miles (the whole)
Now we solve for X, which stands for the total miles driven in September:
0.67 / 1 = 217 / X
To solve for X, we can cross-multiply and then divide:
(0.67) * X = 217 * 1
X = 217 / 0.67
After doing the calculation, we find:
X = 324 miles (approximately)
Therefore, Marshall drove approximately 324 miles in September.