How many triangles are there on the puzzle below?

What's the only room from which no one can enter or leave

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

Can you find the mistake in the below statement?

We know that money can be names differently for the purpose it is used for. Some of the examples of money given at following places or for following activities:

In temple = Daan
In school = Fees
During marriage = Dowry
For divorce = Alimony
Paying government = Tax
In court = Fine
Employer to employee = Salary
To kidnappers = Ransom
For illegal reason = Bribe
To civil servant retirees = Pension

Do you know what do we call the money a husband gives to his wife?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?