The flower will be invisible (almost indistinguishable) against the background of the canvas. The red flower reflects the rays of the red part of the spectrum, the white canvas reflects the rays of all colors. The red filter only transmits red rays. Therefore, the same rays from the flower and the canvas come into the eye of the observer who examines the canvas through the red filter.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.