Can anyone tell me a word in the English dictionary which has a silent 'z'?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

You can see it everyday, But cannot touch it at will. What is it?

Which city is three-fifths chick two third cat and 50% goat?

I always drive my customer away.

Who am I?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

Below, you can see three complete equations and one incomplete. Based on the three complete ones, can you complete the incomplete one?

5 $ 4 $ 3 $ 9 = 4215
6 $ 9 $ 2 $ 6 = 3816
4 $ 7 $ 3 $ 3 = 1122
7 $ 2 $ 7 $ 4 = ____

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?