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

first person does work in 1 minutes = 1/15 of total work

second person does work in 1 minutes = 1/30 of total work

both will do in one minute = 1/15 + 1/30 = 1/10 of total work.

so in ten minutes they will complete the work.

Answer 2

Thank you very much!