Pat can design a website in 20 hours. His friend can design the same site in 30 hours. How long will it take to design the website working together?

I got 12 hrs.

Is this correct?

2 answers

First divide 20 by two and 30 by 2.

You get 10 and 15.

Add the two together:25.

divide 25 by two and you get 12.5

The answer is 12.5
i tried it differently i still get 12hrs?