When can we add 2 to 11 and get 1 as the correct answer?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Find the smallest sentence with all the English alphabet.

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

A research team went to a village somewhere between the jungles of Africa. Luckily for them, they reached the day when quite an interesting custom was to be performed. The custom was performed once a year as they confirmed and was performed in order to collect the taxes from every male of the region.

The taxes were to be paid in the form of grains. Everyone must pay pounds of grain equaling his respective age. This means a 20-year-old will have to pay 20 pounds of grain and a 30-year-old will pay 30 pounds of grain and so on.

The chief who collects the tax has 7 weights and a large 2-pan scale to weigh. But there is another custom that the chief can weigh only three of the seven weights.

Can you find out the weights of the seven weights? Also, what is the maximum age of the man that can be weighed for the payment of taxes?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

I cannot talk, but I always reply when spoken to. What am I?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

The cream is heavier than Milk. True or False?