What does this rebus puzzle means ?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

Find the hidden panda in the image below.

Can you make four (4) nines (9) equal 100?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

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

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?

There is a wide field of corn. A goose finds its way into the field and starts running. Can you find out till which point the goose can run into the field?