If Nora and Owen work together on a project, they will complete it in 10 days. If Owen were to work with Dylan on the same project, they will take a day longer. If Dylan and Grace work together, they will take 110% more time than Nora and Owen. If Nora and Grace were to work together, how many more days will they take to complete the project compared to Owen and Dylan working together?
Time taken by Nora and Owen in percent = 100%
Time taken by Dylan and Grace = 100% + 110% = 210%

Time taken by Nora and Owen = 10 days ---- (1)
Time taken by Owen and Dylan = 11 days ---- (2)
Time taken by Dylan and Grace = 210% x 10 = 21 days ---- (3)

(1) + (2) + (3)
Nora + Owen + Owen + Dylan + Dylan + Grace → 10 + 11 + 21 = 42 days
Nora + 2 (Owen + Dylan) + Grace → 42 days
Nora + Grace + 2 x 11 → 42 days
Nora + Grace → 42 - 22 = 20 days

More days to complete the project for Nora and Grace compared to Owen and Dylan
= 20 - 11
= 9

Answer(s): 9