Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

Your job is to measure 45 minutes if you have only two cords and matches to light the cords.

1. The two cords are twisted from various materials, so their different segments can burn at different rates.
2. Each cord burns from end to end in exactly one hour.

Describe your way of measuring the 45 minutes.

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

I don't get anymore wetter, no matter how much rain falls on me.