If it takes Mary 45 minutes to basic cleaning of her house, and it takes her daughter 65 minutes to do the same basic cleaning, then how many minutes will it take for them to clean together?

Can I please get help with ho to set the equation up?

Mary rooms /minute = 1/45

d rooms/minute = 1/65

together rooms/ minute = 1/45 + 1/65 = .0376 rooms/minute or 1/.0376 = 26.6 minutes per room