It takes 15 machines 15 minutes to make 500 raviolis. The machines produce raviolis at a steady rate. How long would it take 75 of these to make 6000 raviolis?

Answer 1

time is inversely proportional to the number of machines and directly proportional to the number of raviolis

t = 15 min * 15/75 * 6000/500

Answer 2

or
15 machines 15 minutes to make 500 raviolis
75 machines 15 minutes to make 2500 raviolis
75 machines 15(2.4) minutes to make 2500(2.4) raviolis
75 machines 36 minutes to make 6000 raviolis

(the 2.4 comes from 6000/2500)