How many times can you subtract the number two from the number fifty?

Can you count the number of squares in the figure below?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

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?

What number should come in place of the question mark below?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Decode below rebus
D
N
A
T
S , D

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?