Adam can fence their garden in 6 hours, while his brother can do the same job in 10 hours. How long will it take them to do this job together?

Answer 1

1/10 + 1/6 = 16/60 = 8/30 = 4/15

It will take them 15/4 hours = 3 and 3/4 hours = 3 hours and 45 minutes