Can you convert the number zero(0) into a positive number using just one mathematical operator ?

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?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

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

A thief enters a store and threatens the clerk, forcing her to open the safe. The clerk says, “The code for the safe is different every day, and if you hurt me you’ll never get the code.” But the thief manages to guess the code on his own. How did he do it?

What can you deduce from the following BrainBat?

CRY
LMKI

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

What do the following words have in common?

Assess
Banana
Dresser
Grammar
Potato
Revive
Uneven
Voodoo

Why are all black people so quick ?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.