Multiple choice

Kunal can do a work in 10 days while Manish can do the same work in 20 days. They started to work together. After 3 days Kunal left the work and Manish completed it. How many days did Manish work alone for remaining work more than the number of days required when both work together to complete the work? कुनाल एक कार्य को 10 दिनों में कर सकता है जबकि मनीष उसी कार्य को 20 दिनों में कर सकता है| उन्होंने एक साथ कार्य करना प्रारंभ किया| 3 दिनों के बाद कुनाल ने कार्य छोड़ दिया और मनीष ने इसे पूरा किया| मनीष ने आवश्यक दिनों की संख्या कितने दिन अधिक अकेले कार्य किया, जिनमें उन दोनों के साथ कार्य करने पर कार्य को पूरा होना था?

  1. 5 (2/7)

  2. 7 (1/3)

  3. 6 (2/3)

  4. 4 (1/3)

  5. None of these /इनमें से को नहीं

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Kunal's rate: 1/10 work per day. Manish's rate: 1/20 work per day. Combined rate: 3/20 per day. In 3 days together: 3 × 3/20 = 9/20 work done. Remaining: 11/20. Manish does this alone at 1/20 per day, taking 11 days. Total days for Manish: 3 (together) + 11 (alone) = 14 days. If both worked together: 1/(3/20) = 20/3 = 6 2/3 days. Manish worked 14 - 6 2/3 = 7 1/3 days more. But wait - the question asks how many days Manish worked alone MORE THAN the days required when both work together. Manish alone for remaining work = 11 days. Together they'd take 6 2/3 days total. Difference: 11 - 6 2/3 = 4 1/3 days. This matches option D.