If Risa and Alexander work together on a project, they will complete it in 5 days. If Alexander were to work with Ella on the same project, they will take a day longer. If Ella and Evelyn work together, they will take 60% more time than Risa and Alexander. If Risa and Evelyn were to work together, how many more days will they take to complete the project compared to Alexander and Ella working together?
Time taken by Risa and Alexander in percent = 100%
Time taken by Ella and Evelyn = 100% + 60% = 160%

Time taken by Risa and Alexander = 5 days ---- (1)
Time taken by Alexander and Ella = 6 days ---- (2)
Time taken by Ella and Evelyn = 160% x 5 = 8 days ---- (3)

(1) + (2) + (3)
Risa + Alexander + Alexander + Ella + Ella + Evelyn → 5 + 6 + 8 = 19 days
Risa + 2 (Alexander + Ella) + Evelyn → 19 days
Risa + Evelyn + 2 x 6 → 19 days
Risa + Evelyn → 19 - 12 = 7 days

More days to complete the project for Risa and Evelyn compared to Alexander and Ella
= 7 - 6
= 1

Answer(s): 1