Thomas can do a job in 4 hours. Julia can do the same job in 6 hours. How many hours will it take the two of them to do the job it they work together?
Not quite.
Their combined rate of doing the rob is
1/4 job/h + 1/6 job/h = 5/12 job/h
5/12 job/h * T (hr) = 1 job
T = 12/5 = 2 2/5 hours
Thanks, again -- DrWLS. You're absolutely right -- and I was wrong.
Maybe they stood around chatting for the additional 6 minutes? <G>
To find out how long it will take Thomas and Julia to complete the job when working together, we can use the concept of "work rates".
First, let's find the work rate of Thomas. Since Thomas can do the job in 4 hours, he completes 1/4th of the job in 1 hour. Similarly, Julia completes 1/6th of the job in 1 hour.
To calculate the combined work rate of Thomas and Julia when working together, we just need to add their individual work rates. So, the combined work rate is 1/4 + 1/6.
To find the time it will take for them to complete the job together, we can take the reciprocal of the combined work rate. In other words, we can invert the fraction value 1/4 + 1/6 to get 6/24 + 4/24 = 10/24.
Therefore, Thomas and Julia will complete the job together in 24/10 hours, which simplifies to 2.4 hours or 2 hours and 24 minutes.
With two of them working together, then their times will be cut in half. Thomas can do it in 2 hours, while Julia does it in 3 hours.
(2 + 3)/ 2 = 2 1/2 hours