Final answer:
C. 12.Rosa placed a total of 11 cones, accounting for 10 intervals of three thousand inches and the initial cone at her starting point.
Step-by-step explanation:
The correct answer is option B. 11. To solve this, we need to determine how many intervals Rosa created by placing cones every 3000 inches. If Rosa walked thirty thousand inches in total and placed a cone every three thousand inches, we simply divide 30,000 by 3,000 to find the number of intervals between the cones, which gives us 10.
However, we must remember to include the first cone that she placed outside of her house, which does not require her to walk any distance. When we add this initial cone to the 10 intervals, we determine that Rosa placed a total of 11 cones.
The correct answer is option C. Rosa put down 12 cones. We can solve this problem by setting up an equation. Let's assume that she put down 'x' cones. We know that each cone is placed 3,000 inches apart, so the total distance covered is equal to the product of the number of cones and the distance between them. Therefore, 3,000 * (x-1) is equal to 30,000.
To solve for x, we can set up the equation: 3,000 * (x-1) = 30,000. Simplifying this equation, we get 3,000x - 3,000 = 30,000. Adding 3,000 to both sides, we get 3,000x = 33,000. Dividing both sides by 3,000, we find that x = 11.
This means that Rosa put down 11 cones, but we also need to consider the first cone she put down outside her house. So, she actually put down 11 + 1 = 12 cones.