Two Strings Brain Teaser

There are 2 pieces of string. Each piece is made of a different material and they are of different lengths. Both pieces of string take exactly 1 hour to burn from one end to the other end. The speed of burning is not uniform throughout, so they can burn quickly first, then slowly at the end or in any random way. If you are given only these 2 pieces of string and a box of matches, how do you measure 45 minutes?
The solution only requires you to burn the strings. No other actions like cutting, measuring, folding etc. is involved.

U2 Crossing the Bridge Brain Teaser

“U2″ has a concert that starts in 17 minutes and all band members must cross a bridge to get there.
All four men begin on the same side of the bridge.
You must organize them so that they all cross to the other side in time. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man’s pace:
Bono: - takes 1 minute to cross
Edge: - takes 2 minutes to cross
Adam: - takes 5 minutes to cross
Larry: - takes 10 minutes to cross
For example: if Bono and Larry walk across first, 10 minutes have elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have elapsed and you have failed the mission.
There is no trick. It is the simple movement of resources in the appropriate order. There are two known answers.

Blind Men

There was a man who went to the mall where he bought 3 pairs of red socks and 3 pairs of white socks. Another man who had already bought 3 pairs of red socks and 3 pairs of white socks came back to return his 6 pairs. They were both blind. As they were walking, they bumped into each other. All the socks scattered around the floor, but each pair remained held together by a rubber band. Nobody helped them pick the socks up, but in 3 minutes they both had 3 pairs of red, and 3 pairs of white. How is that possible if they are blind?