I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

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?

I am first found in caves, now prolific online; I am a depiction, a drawing, a symbol, or sign. I will convey whichever mood you could wish; or for that matter, a fist, flask, or fish. What am I?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What is the centre of gravity?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

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

Using Only Five 5's and any mathematical operator make sum as 37

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?