If Sofia and Ryan work together on a project, they will complete it in 9 days. If Ryan were to work with Grace on the same project, they will take a day longer. If Grace and Ethan work together, they will take 100% more time than Sofia and Ryan. If Sofia and Ethan were to work together, how many more days will they take to complete the project compared to Ryan and Grace working together?
Time taken by Sofia and Ryan in percent = 100%
Time taken by Grace and Ethan = 100% + 100% = 200%

Time taken by Sofia and Ryan = 9 days ---- (1)
Time taken by Ryan and Grace = 10 days ---- (2)
Time taken by Grace and Ethan = 200% x 9 = 18 days ---- (3)

(1) + (2) + (3)
Sofia + Ryan + Ryan + Grace + Grace + Ethan → 9 + 10 + 18 = 37 days
Sofia + 2 (Ryan + Grace) + Ethan → 37 days
Sofia + Ethan + 2 x 10 → 37 days
Sofia + Ethan → 37 - 20 = 17 days

More days to complete the project for Sofia and Ethan compared to Ryan and Grace
= 17 - 10
= 7

Answer(s): 7