It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Buy me, smell me or deliver me, I do not change.

Who am I?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

I left my campsite and hiked south for 3 miles. Then I turned east and hiked for 3 miles. I then turned north and hiked for 3 miles, at which time I came upon a bear inside my tent eating my food! What colour was the bear?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

A man dies of old age on his 25 birthday. How is this possible?

A new clothing store has a unique method of pricing items. A vest costs $20, a tie costs $15, a blouse costs $30, and underwear costs $45. How much would pants cost?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

what does the below rebus mean?