What does this mathematical rebus means ?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

Five lovely ladies(Sophia, Isabella, Madison, Emma and Olivia) planned a picnic.

They each buy one thing each for the picnic.

Sophia, Emma and Olivia got a drink : orange-Juice, apple-juice, and mango-juice.
Olivia got the drink with the same letter as the one in her first name.
Emma loves mango-juice.
The other two bring some food : chocolates and pizza.
Also Madison is allergic to cheese.

So which ladies bought what ?

In a secret society, a buried chamber can be accessed only via a secret password. The password is seven characters long and comprises of just letters and numbers.

You find a code that can help you in cracking the password. The code says "You force heaven to be empty".

Can you deduce the password from that?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Be active and find the killer in the picture Riddle below.

What am I?

Spot 5 differences in two Christmas tree below:

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.