Why is a river so rich ?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

A devotee visits 9 temples when he visits India. All these nine temples have one thing in common - there are 100 steps in every temple. The devotee puts the Re.1 coin after climbing up every step. He does the same while climbing down every step. At each temple, the devotee offers half of his money from his pocket to god. In this way, his pocket becomes empty after he visits the 9th temple.

Can you calculate the total amount he had initially?

Can you name an animal whose killing cannot be performed without spilling your own blood?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

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

How do you go from 98 to 720 using just one letter?

'S' refers to the number of seconds in a day and 'H' refers to the number of hours in ten years. Which quantity out of these two is greater?

How far can you walk into the woods?

Find the missing number in the sequence below: