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

Time taken by Jack and Riordan = 10 days ---- (1)
Time taken by Riordan and Hannah = 11 days ---- (2)
Time taken by Hannah and Joseph = 210% x 10 = 21 days ---- (3)

(1) + (2) + (3)
Jack + Riordan + Riordan + Hannah + Hannah + Joseph → 10 + 11 + 21 = 42 days
Jack + 2 (Riordan + Hannah) + Joseph → 42 days
Jack + Joseph + 2 x 11 → 42 days
Jack + Joseph → 42 - 22 = 20 days

More days to complete the project for Jack and Joseph compared to Riordan and Hannah
= 20 - 11
= 9

Answer(s): 9