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

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

John needs to purchase 100 chocolates from three different shops and he has exactly 100 rupees to do that which he must spend entirely. He must buy at least 1 Chocolate from each shop.

The first shop is selling each chocolate at 5 paise, the second is selling at 1 rupee and the third is selling at 5 rupees.

How many chocolates should he buy from each shop?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Can you name some countries which do not have the alphabet 'A' in them?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?