What does the below rebus riddle means?

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?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

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

How many letters are in the alphabet?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?