The distance between John’s home and the park is 3000m. John walked from his home to the park at a speed of 100m per minute and then walked back home at a speed of 150m per minute. What is the John’s average speed in meter per minute?
One class has 60 students. Among them, 3/5 are female students. How many male students?
One class has 50 students. Among them, 2/5 are female students. How many male students?