Richard and Marie can complete a task of writing in 2 days when working…
2024
Richard and Marie can complete a task of writing in 2 days when working together, if Richard alone go for typing he need 12 days to complete, Marie can complete the same task when working in.
- A.
11/5 days
- B.
12/3 days
- C.
12/5 days
- D.
13/5 days
Attempted by 37 students.
Show answer & explanation
Correct answer: C
Solution:
Use work rates (fraction of the job done per day).
Richard’s rate = 1 job / 12 days = 1/12 job per day.
Together they finish in 2 days, so combined rate = 1 job / 2 days = 1/2 job per day.
Marie’s rate = combined rate − Richard’s rate = 1/2 − 1/12 = 5/12 job per day.
Time for Marie alone = 1 ÷ (Marie’s rate) = 1 ÷ (5/12) = 12/5 days.
Final answer: Marie can complete the task alone in 12/5 days.