If Alexander and Sofia work together on a project, they will complete it in 10 days. If Sofia were to work with Harper on the same project, they will take a day longer. If Harper and Risa work together, they will take 70% more time than Alexander and Sofia. If Alexander and Risa were to work together, how many more days will they take to complete the project compared to Sofia and Harper working together?
Time taken by Alexander and Sofia in percent = 100%
Time taken by Harper and Risa = 100% + 70% = 170%

Time taken by Alexander and Sofia = 10 days ---- (1)
Time taken by Sofia and Harper = 11 days ---- (2)
Time taken by Harper and Risa = 170% x 10 = 17 days ---- (3)

(1) + (2) + (3)
Alexander + Sofia + Sofia + Harper + Harper + Risa → 10 + 11 + 17 = 38 days
Alexander + 2 (Sofia + Harper) + Risa → 38 days
Alexander + Risa + 2 x 11 → 38 days
Alexander + Risa → 38 - 22 = 16 days

More days to complete the project for Alexander and Risa compared to Sofia and Harper
= 16 - 11
= 5

Answer(s): 5