5 (1) is proportional. Total number of pencils: number of boxes = number of pencils per box (certain proportion) (2) inversely proportional. The number of students × per capita floor space = classroom area (certain proportion) (3) is inversely proportional. Total number of parts produced: number of people needed = number of parts produced by each person (certain proportion) (4) inversely proportional. The number of TV sets made every day × the number of days of use = the total number of TV sets (certain products) (5) is inversely proportional. Sowing amount per hectare × number of hectares sown = total amount of seeds (a certain product)
Answer 6:2.5 hours 150km, 4.5 hours and 270km.