If Rachel and Jacob work together on a project, they will complete it in 10 days. If Jacob were to work with Layla on the same project, they will take a day longer. If Layla and Joseph work together, they will take 80% more time than Rachel and Jacob. If Rachel and Joseph were to work together, how many more days will they take to complete the project compared to Jacob and Layla working together?
Time taken by Rachel and Jacob in percent = 100%
Time taken by Layla and Joseph = 100% + 80% = 180%

Time taken by Rachel and Jacob = 10 days ---- (1)
Time taken by Jacob and Layla = 11 days ---- (2)
Time taken by Layla and Joseph = 180% x 10 = 18 days ---- (3)

(1) + (2) + (3)
Rachel + Jacob + Jacob + Layla + Layla + Joseph → 10 + 11 + 18 = 39 days
Rachel + 2 (Jacob + Layla) + Joseph → 39 days
Rachel + Joseph + 2 x 11 → 39 days
Rachel + Joseph → 39 - 22 = 17 days

More days to complete the project for Rachel and Joseph compared to Jacob and Layla
= 17 - 11
= 6

Answer(s): 6