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

Time taken by Christian and Michael = 10 days ---- (1)
Time taken by Michael and Henry = 11 days ---- (2)
Time taken by Henry and Charlotte = 180% x 10 = 18 days ---- (3)

(1) + (2) + (3)
Christian + Michael + Michael + Henry + Henry + Charlotte → 10 + 11 + 18 = 39 days
Christian + 2 (Michael + Henry) + Charlotte → 39 days
Christian + Charlotte + 2 x 11 → 39 days
Christian + Charlotte → 39 - 22 = 17 days

More days to complete the project for Christian and Charlotte compared to Michael and Henry
= 17 - 11
= 6

Answer(s): 6