Answer: Mai has ridden 30% of the course
Step-by-step explanation: Course is 60 miles long, 15 × 4 = 60 ÷ 1/4 = 15, 6×10 = 60 and 6÷2 = 3. 15 would be 25% of the course, 3 would be 5% of the course. Add this together 15+3 = 18 miles you would get she's ridden 30% of the course
