Question

One person can do a certain job in fifteen minutes, and another person can do the same job in thirty minutes. How many minutes will it take them to do the job together?
5 min
10 min
20 min

Answer 1

10 min 

1/15
1/30

1/15+1/30 = 3/30 = 1/10

Answer 2

it will take 10 minutes babe