सहा अनुभवी माणसे आणि आठ अननुभवीमाणसे एक काम 10 दिवसात पूर्ण करतात. तेच काम 26 अनुभवी माणसे आणि 48 अननुभवी माणसांनी केले, तर दोन दिवसांत पूर्ण होते. जर याच कामासाठी 15 अनुभवी माणसे आणि 20 अननुभवी माणसे लावली तर ते पूर्ण करण्यासाठी किती दिवस लागतील ?

The correct answer is Option A (4 days).

Key Points:
• Let the 1-day work of an experienced man be x and an inexperienced man be y.
• From the first condition: 10(6x + 8y) = 1 ⇒ 60x + 80y = 1 (Total Work)
• From the second condition: 2(26x + 48y) = 1 ⇒ 52x + 96y = 1
• Equating the two: 60x + 80y = 52x + 96y ⇒ 8x = 16y ⇒ x = 2y (An experienced man is twice as efficient).
• Substitute x=2y in 60x + 80y = 1 ⇒ 60(2y) + 80y = 1 ⇒ 120y + 80y = 1 ⇒ 200y = 1 ⇒ y = (1)/(200).
• Then x = (2)/(200) = (1)/(100).
• Now, work done by 15 experienced and 20 inexperienced men in 1 day = 15x + 20y = 15((1)/(100)) + 20((1)/(200)) = (15)/(100) + (10)/(100) = (25)/(100) = (1)/(4).
• Therefore, they will complete the work in 4 days.
• Key Takeaway: Equate total work scenarios to find the efficiency ratio between workers, then calculate the required days.