Rates and ratio problems

Question

Amy needs 1 hour to do a certain job. Her dad can do the same job in 30 min. How many minute will it take them to do the job of they work together at given rates?

Answer 1

Amy takes an hour so she does

1/60 of yhe job per minute

Father takes 30 mins so he does

1/30 of the job per minute

 

together they complete

1/60 + 1/30 per minute 

or 3/60 of the job per minute

 

(3/60)x = 1

x = 60/3

x = 20 minutes

Answer 2

20 min

i typed 20 min

funny wyzant says "Your answer must be between 20 and 10000 characters."