A bread making machine can make bread of 50 kg dough in 3 minutes. How many such machines are required?

One machine makes 50 kg bread in 3 mins

So it will make 100 kg in 6 mins.

So number of machines required

to make 300 kg bread in 6 mins = 300/100 = 3

3 machines are required to make 30 kg bread in 6 mins.