Bill and Ben can clean the garage together in 6 hours. If it takes Bill 10 hours working alone, how long will it take Ben working alone?
সমাধান
সঠিক উত্তর: Option C
Ben একা করতে পারে =(10 ×6)/(10 -6)
=(10 ×6)/4
=15 ঘণ্টায়