AB, AC and BC are the diameters of three circles shown on the diagram, what percentage of the largest circle is unshaded?

Câu 1: AB, AC and BC are the diameters of three circles shown on the diagram. Given that AB∶BC=3∶2, what percentage of the largest circle is unshaded? Câu 2 Marry walks from the book store to school at a speed of 70 m/min. 2 minutes later, Bean also leaves for school from the book store at a speed 80 m/min. Mr Bean arrives at school 2 minutes before Marry. What is the distance between the book store and the school? Ảnh của câu 1 nha