Xiaohua stopped for a few minutes on the way to the library. 40-20=20 minutes How many minutes did it take to borrow books from the library? 100-60= 40 minutes from home to the library, how many kilometers per hour is the average speed? 5 ÷ 2/3 = 7.5km, what is the average speed to go home from the library? 5÷ 1/3= 15 km How many kilometers did Xiao Hua Yi ride? What is the average speed of 5×2= 10 km round trip? 10 ÷ (2/3+1/3) =10 km