Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

What has many keys but can’t open a single lock?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

What occurs twice in a week, once in a year but never in a day?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

One night, a woman receives a call from the police. They tell her that her husband was murdered and that she should come to the crime scene as soon as possible. The woman drops the phone, shocked, and drives 20 minutes to the crime scene. As soon as she reaches the crime scene, the police arrest her and she is convicted of murder. How do the police know she committed the crime?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?