Final answer:
When you shine a blue, red, and green flashlight at a white index card, the index card will appear to be the color of the flashlight that you are shining on it.
Step-by-step explanation:
When you shine a blue flashlight, red flashlight, and green flashlight at a white index card, you will observe that the index card appears to be the color of the flashlight that you are shining on it. This is because the color of an object is determined by the wavelengths of light that it reflects. For example, if you shine a blue flashlight on the index card, it will reflect blue light and appear blue. Similarly, if you shine a red flashlight on the index card, it will reflect red light and appear red.