susan can paint a chair in 3 hours. jerry can paint in the same size 2.5 hours. working together, how long will it take to paint 10 chairs?
Susan's rate = 1/3
Jerry's rate = 1/2.5
combined rate = 1/3 + 1/2.5 = 11/15
so time taken to do one chair = 1/(11/15) = 15/11
so to do 10 chairs will take 10(15/11) hours
or 13.636 hours. or 13 hours and appr. 38 minutes
To find out how long it will take to paint 10 chairs when Susan and Jerry work together, we need to determine their combined painting rate.
Susan can paint a chair in 3 hours, which means her painting rate is 1 chair per 3 hours.
Jerry can paint a chair in 2.5 hours, which means his painting rate is 1 chair per 2.5 hours.
To find their combined painting rate, we can add their individual rates together:
1/3 + 1/2.5 = (5/15) + (6/15) = 11/15
So, Susan and Jerry together can paint approximately 11/15 of a chair in one hour.
Now, we can use this combined painting rate to calculate the time it will take to paint 10 chairs.
To find the time, we can set up a ratio:
(11/15) chairs / 1 hour = 10 chairs / x hours
Cross-multiplying:
(11/15) * x = 10
Solving for x:
x = 10 * (15/11) = 150/11 ≈ 13.6
Therefore, it will take approximately 13.6 hours for Susan and Jerry to paint 10 chairs when working together.