An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

A game is being played where eight players can last for thirty-five minutes. Six substitutes alternate with each player in this game. Thus, all players are on the pitch for the same amount of time including the substitutes.

For how long is each player on the pitch?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Find the missing number in the image below.

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What can you catch but never throw?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?