উত্তর সিলেক্ট করলে সঠিক ও ভুল দেখাবে।
ব্যাখ্যা ও সঠিক সমাধান
উত্তর:
2 hours
Here, 2 large and 1 small pumps ≡ 1 large and 3 small pumps
Again, 3 large and 4 small pumps
= 2 large and 1 small pumps + 1 large and 3 small pumps
= 2 large and 1 small pumps + 2 large and 1 small pumps
= 2 x (2 large and 1 small pumps)
Now, 2 large and 1 small pumps can fill the tank in 4 hours
So, 2 x (2 large and 1 small pumps) can fill the tank = 4/2 = 2 hours