Why is a river so rich ?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Can you divide the below-given shape into four equal and identical pieces?

What number divided by 4 is the same as that number minus 4?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

The picture shows the dice results in each couple of throws. If they are actually following a pattern, can you find out the missing one?

I add 5 to 9 and get 2. The answer is correct, so what am I?

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.