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Smita can finish a work in 12 days and Sam can finish the same work in 9 days.After working together for 4 days they both leave the job. What is the fraction of unfinished work?
- A1/2
- B7/9
- C2/9
- D1/4
Answer not set
Discussion 1
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CCommunity
Work done by Smita in one day = 1/12
Work done by Sam in one day = 1/9
Work done by Smita and Sam together in one day = (1/12) + (1/9) = 7/36
Work done by Smita and Sam together in 4 days = 4 × 7/36 = 7/9
The fraction of unfinished work = 1 – 7/9 = 2/9
∴ The fraction of unfinished work = 2/9
Work done by Sam in one day = 1/9
Work done by Smita and Sam together in one day = (1/12) + (1/9) = 7/36
Work done by Smita and Sam together in 4 days = 4 × 7/36 = 7/9
The fraction of unfinished work = 1 – 7/9 = 2/9
∴ The fraction of unfinished work = 2/9