When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Can you find the mistake in the below statement?

During which month do people sleep the least?

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?

Can you count the number of children in the picture below

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

A bomb exploded in a room full of married couples and no one died. How?

I have eight fingers and two thumbs but I do not live. What Am I?

A bridge is about to collapse. There are four people P, Q, R and S on one of the sides. Before the bridge collapses, they want to cross it. Now since the bridge is too weak, it can only stand the weight of two people at a time. Also, it is night time and nothing is visible. They have just one torch with them.

Now P takes one minute to cross the bridge, Q takes two minutes to cross, R takes five minutes to cross and S takes ten minutes to cross.

The bridge will collapse in seventeen minutes. How will they be able to cross the bridge before it collapses?

Can you find the key in the picture below?