If Lilian and Matthew work together on a project, they will complete it in 5 days. If Matthew were to work with Julian on the same project, they will take a day longer. If Julian and Natalie work together, they will take 180% more time than Lilian and Matthew. If Lilian and Natalie were to work together, how many more days will they take to complete the project compared to Matthew and Julian working together?
Time taken by Lilian and Matthew in percent = 100%
Time taken by Julian and Natalie = 100% + 180% = 280%

Time taken by Lilian and Matthew = 5 days ---- (1)
Time taken by Matthew and Julian = 6 days ---- (2)
Time taken by Julian and Natalie = 280% x 5 = 14 days ---- (3)

(1) + (2) + (3)
Lilian + Matthew + Matthew + Julian + Julian + Natalie → 5 + 6 + 14 = 25 days
Lilian + 2 (Matthew + Julian) + Natalie → 25 days
Lilian + Natalie + 2 x 6 → 25 days
Lilian + Natalie → 25 - 12 = 13 days

More days to complete the project for Lilian and Natalie compared to Matthew and Julian
= 13 - 6
= 7

Answer(s): 7