Greg practiced playing his clarinet for 12 minutes. He has practiced 40% of the amount of time he needs to practice today. How many more minutes does Greg need to practice today?
I believe the answer is he needs 30 more minutes. This would make him be practicing 42 minutes in all. I got this by doing 12 over x equal 40 over 100. then you cross multiply the two and you get 1200 over 40. That reduced is 30. Hope I helped! :)