If Riordan and Hazel work together on a project, they will complete it in 6 days. If Hazel were to work with Oliver on the same project, they will take a day longer. If Oliver and Rachel work together, they will take 100% more time than Riordan and Hazel. If Riordan and Rachel were to work together, how many more days will they take to complete the project compared to Hazel and Oliver working together?
Time taken by Riordan and Hazel in percent = 100%
Time taken by Oliver and Rachel = 100% + 100% = 200%

Time taken by Riordan and Hazel = 6 days ---- (1)
Time taken by Hazel and Oliver = 7 days ---- (2)
Time taken by Oliver and Rachel = 200% x 6 = 12 days ---- (3)

(1) + (2) + (3)
Riordan + Hazel + Hazel + Oliver + Oliver + Rachel → 6 + 7 + 12 = 25 days
Riordan + 2 (Hazel + Oliver) + Rachel → 25 days
Riordan + Rachel + 2 x 7 → 25 days
Riordan + Rachel → 25 - 14 = 11 days

More days to complete the project for Riordan and Rachel compared to Hazel and Oliver
= 11 - 7
= 4

Answer(s): 4