What English word has three consecutive double letters?

Solve the equation in the image by looking at the pattern closely.

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

When it is alive we sing, when it is dead we clap our hands. What is it?

How many sides does a circle have?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

Whats the next number in the below number sequence pattern.

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

What does it mean?

Can you count the number of quadrilaterals in the picture below?