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?
yes
Thank you.
To determine how long it will take for Pat and his friend to design the website working together, you need to use the concept of work rates.
The work rate is the amount of work done per unit of time. In this case, Pat's work rate is 1 website per 20 hours, and his friend's work rate is 1 website per 30 hours.
To find the work rate when they work together, you need to add their work rates. So, their combined work rate is 1 website per (1/20 + 1/30) hours.
To simplify this, you need to find a common denominator for 20 and 30, which is 60.
1/20 + 1/30 = 3/60 + 2/60 = 5/60
So, their combined work rate is 1 website per 5/60 hours, which is equivalent to 12 hours.
Yes, your answer of 12 hours is correct.