A word I know has six letters it contains, remove one letter and 12 remain. What is it?

In an Art Gallary, When the clock hit 11 am, Artist hung the painting number 30. When it struck 4 pm, he hung painting number 240 and when it struck 7:30 pm, he hung painting number 315.

Can you determine, which painting number will he hang when the time is 9:20 pm?

Can you decipher the below rebus?

PBLUESAISNUERSES

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

Can you place three balls such that the equation shown in the picture holds true?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

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?

How many triangles can you find in this given picture?