Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Tell me the Hindi name of a Vegetable which if we remove 1st word will become a precious Stone and by removing the last word it will become a sweet eatable.

A father's child, a mother's child, yet no one's son.

Who am I?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

Joseph organises an exotic office New year party at the beach to his important fellow employees.

Following are the important people that will come to the party

1. Joseph

2. Joseph 2 girlfriends- Carol Vanstone and Tracey Hughes

3. The sales head Clay Vanstone.

4. Clay Vanstone 2 associates.

5. Mr. Jeremy and his Secret Tab.

They all need to cross a small river to reach the beach, however, Joseph has got just one boat.

There are few rules for crossing the river.

1. The capacity of the boat is limited to just two people.

2. Clay Vanstone associates will not stay with Joseph without Clay Vanstone.

3. Carol Vanstone and Tracey Hughes will not stay with the Clay Vanstone without Joseph.

4. Mr. Jeremy would never leave the Secret Tab alone.

5. Secret Tab counts as a person.

6. Only Joseph, Clay Vanstone or Mr. Jeremy can drive the boat.

7. The two girlfriends Carol Vanstone and Tracey Hughes will not stay with the Clay Vanstone without Joseph.

8. No Associates would stay with Joseph without their Clay Vanstone.

9. Mr.Jeremy will not leave the Secret Tab alone.

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

By moving just one matchstick, you need to make the below statement true. Can you do it?

Suppose that you are trapped on the surface of a frozen lake. The surface is so smooth and ideal that there is no friction at all. You cant make any grip on the ice and no wind is blowing to help you out. You have just a mobile phone with you which has got no reception disabling you to call for help.

How will you plan your escape before you freeze to death on the frozen lake?