Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

What kind of tree can you carry in your hand?

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

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

You can see three almost identical images below. Can you spot the odd one out from them?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

What is the largest number you can write with just 3 digits?