If Stella and Luke work together on a project, they will complete it in 10 days. If Luke were to work with Scarlett on the same project, they will take a day longer. If Scarlett and Josiah work together, they will take 90% more time than Stella and Luke. If Stella and Josiah were to work together, how many more days will they take to complete the project compared to Luke and Scarlett working together?
Time taken by Stella and Luke in percent = 100%
Time taken by Scarlett and Josiah = 100% + 90% = 190%

Time taken by Stella and Luke = 10 days ---- (1)
Time taken by Luke and Scarlett = 11 days ---- (2)
Time taken by Scarlett and Josiah = 190% x 10 = 19 days ---- (3)

(1) + (2) + (3)
Stella + Luke + Luke + Scarlett + Scarlett + Josiah → 10 + 11 + 19 = 40 days
Stella + 2 (Luke + Scarlett) + Josiah → 40 days
Stella + Josiah + 2 x 11 → 40 days
Stella + Josiah → 40 - 22 = 18 days

More days to complete the project for Stella and Josiah compared to Luke and Scarlett
= 18 - 11
= 7

Answer(s): 7