Logical Puzzles - General Questions

You have a 3-litre jug and a 5-litre jug and unlimited water. What is the minimum number of pourings (fill, empty or transfer) to measure exactly 4 litres?

A brick weighs 1 kg plus half a brick. How much does the brick weigh?

If you rearrange the letters of 'LISTEN', you can make which word?

You have two coins that add up to Rs. 15. One of them is not a Rs. 10 coin. What are the two coins?

You have 8 identical-looking balls; one is heavier. With a simple balance, what is the minimum number of weighings needed to find it for certain?