What is the minimum number of pourings needed to get 4 litre of milk from a fully filled 8 litre can, using ungraduated empty 5 and 3 litre cans? No milk should be wasted.

Correct option is C

​Solution:

We are given a fully filled 8-litre can and ungraduated empty 5-litre and 3-litre cans. We need to get exactly 4 litres of milk, without wasting any.

To solve this, we will follow a step-by-step procedure using the minimum number of pourings.

Step-by-step process:

1. Fill the 5-litre can from the 8-litre can:

   • Now the 5-litre can has 5 litres, and the 8-litre can has 3 litres remaining.
   • Pouring count: 1

2. Pour the 5 litres from the 5-litre can into the 3-litre can:

   • The 3-litre can is now full, and 2 litres remain in the 5-litre can.
   • Pouring count: 2

3. Empty the 3-litre can:

   • Now the 3-litre can is empty.
   • Pouring count: 3

4. Pour the 2 litres from the 5-litre can into the 3-litre can:

   • The 3-litre can now contains 2 litres.
   • Pouring count: 4

5. Fill the 5-litre can again from the 8-litre can:

   • Now the 5-litre can contains 5 litres, and the 8-litre can has 0 litres remaining.
   • Pouring count: 5

6. Pour from the 5-litre can into the 3-litre can (which already contains 2 litres):

   • The 3-litre can will take 1 litre to become full, leaving 4 litres in the 5-litre can.
   • Pouring count: 6

Now we have 4 litres in the 5-litre can.

Conclusion:

The minimum number of pourings required to get exactly 4 litres is 6.

Thus, the correct answer is (c) 6.