WBCS.LIVE practice question

A can finish a work in 12 days and B can do it in 18 days. After working together for 4 days, A leaves. How many more days will B take to finish the remaining work?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. 6 days
  2. 8 days
  3. 10 days
  4. 5 days

Correct answer and explanation

Correct answer: 8 days

Explanation: ✅ Correct Answer: (B) 8 days 📚 Explanation: Step-1: Find 1-day work. A = 1÷12, B = 1÷18. Their combined 1-day work = (1÷12 + 1÷18) = (3+2)÷36 = 5÷36. Step-2: Work done in 4 days = 4 x (5÷36) = 20÷36 = 5÷9. Remaining work = 1 - 5÷9 = 4÷9. Step-3: B's 1-day work is 1÷18. Time taken by B for remaining work = (4÷9) / (1÷18) = (4÷9) x 18 = 8 days.