Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

Two Twins Jack and Jill were standing back to back and suddenly they started running in opposite direction for 4 kilometres and then turn to left and run for another 3 kilometres.

what is the distance between the Baggio twins when they stop ?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

What does a man do only once in his lifetime, but women do once a year after they are 29?

What four weights can be used to balance from 1 to 30 pounds?