What number comes next in the series?

5 15 5 18 5 24 14 20 _

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

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?

If a wheel has 54 spokes, how many spaces are there between the spokes?

What can you catch but never throw?

I am white when I am dirty, and black when I am clean. What am I?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

Can you count the number of triangles in the given picture?

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?

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?