Math work assignment please help me i am stuck

Question

Beck finished 30% of his homework in 12 minutes. How many minutes will it take him to complete all of his homework?

Answer 1

12/30 = X/100, ratio of time to percent is equal

12/3 = X/10

4 =X/10

X =40 minutes to complete all the homework

30% in 12 minutes, 3 times that means 90% in 36 minutes

10% in 1/3 time or 4 minutes 36+4 = 40 minutes for 90%+10% = 100%