Multiple choice

A work is started by a man and it is assumed that he will finish the work in 11 days if working alone. Each subsequent day a new man joined the work. In how many days the four times the original work will be completed, if after the 8th day from the starting of the work no new man will be further added? एक काम एक आदमी द्वारा शुरू किया जाता है और यह माना जाता है कि वह अकेले काम करने पर 11 दिनों में काम खत्म कर देगा। प्रत्येक दिन के बाद एक नया आदमी काम में शामिल हुआ। प्रारंभिक कार्य के चार गुने कार्य को कितने दिनों में पूरा किया जाएगा, यदि कार्य शुरू होने के 8 वें दिन के बाद कोई नया आदमी आगे नहीं जोड़ा जाएगा?

  1. 5

  2. 6

  3. 7

  4. 8

  5. 9

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

Man's rate = 1/11 work per day. Days 1-8: men increase from 1 to 8. Days 9 onwards: 8 men work constantly. For 4× work: First 8 days complete sum(1 to 8)/11 = 36/11 units. Remaining: 4 - 36/11 = 8/11 units. With 8 men: (8/11)/(8/11) = 1 day. Total = 8 + 1 = 9 days. Option E is correct. The key insight is that after day 8, the workforce stabilizes at 8 men.