I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

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?

What is the riddle which can be asked all day with a different correct answer each time.

What is black when you buy it, red when you use it, and gray when you throw it away?

You see me once in June, twice in November, and not at all in May. What am I?

Where do you go to learn how to make ice cream?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?