Two Different Hoses With Different Taps Are Used To Fill A Pond 1hose Takes 20minutes And The Other Takes 30minutes How Many Minutes Does It Take Using Both Ho

math question and the answer is 12 but how do you work it out? Thanks so much

Solution

if the 1st hose takes 20 mins then it fills 1/20 per minute The 2nd hose takes 30 mins so it fills 1/30 per minute Together they fill  1/20 + 1/30 = 3/60 + 2/60 = 5/60 = 1/12 per minute   (1/12)m = 1 m = 12 minutes