2

45

six

24 18

eight

six

1.5

Two. 2 pairs

6 pairs

All other errors

Three. four

six

eight

Answer; The quantity and time of daily transportation are inversely proportional, because the product of the corresponding quantities of these two changes is certain.

Four. 1 ... First, it can be proportional, directly proportional, because

Travel time = speed

2.. 1600 divided by 20- 150 divided by 20 = 5 (km/h) a —————————————

3..5×2.5= 12.5(km) Answer ——————————————————————.

Answer, write it yourself.