I’m tall when I’m young, and I’m short when I’m old. What am I?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?

Find the next number in the sequence

5 12 24 36 ?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?