Question
It takes Machine E and Machine B 10 minutes to print a total of 520 copies of posters. Machine E can print 21 copies of posters in one minute. How many copies of posters can Machine F print per minute?
2 m

Click button first when a symbol is required. X

It takes Machine E and Machine B 10 minutes to print a total of 520 copies of posters. Machine E can print 21 copies of posters in one minute. How many copies of posters can Machine F print per minute?