19. Five marks exercise problems X

1. Neelaveni goes by bi-cycle to her school every day. Her average speed is $12 \ km/hr$ and she reaches school in $20$ minutes. What is the increase in speed, if she reaches the school in $15$ minutes?

 

$km/hr$

 

2. A toy company requires $36$ machines to produce car toys in $54$ days. How many machines would be required to produce the same number of car toys in $81$ days?

 

machines