Two Ropes

You are given two ropes and a lighter. This is the only equipment you can use. You are told that each of the two ropes has the following property: if you light one end of the rope, it will take exactly one hour to burn all the way to the other end. But it doesn’t have to burn at a uniform rate. In other words, half the rope may burn in the first five minutes, and then the other half would take 55 minutes.

The rate at which the two ropes burn is not necessarily the same, so the second rope will also take an hour to burn from one end to the other, but may do it at some varying rate, which is not necessarily the same as the one for the first rope. Now you are asked to measure a period of 45 minutes.

How will you do it?

by looking at your watch?

Burn both sides of the first rope and one side of the second one. After 30 minutes the first rope will be fully consumed and only half of the second one will be consume. Then light up the other half of the second rope and it will take 15 minutes to burn the rest of it because 30 minutes of the second rope has already been burn.

correct

Oh wow !! I am so intelligent

In facts you just need to think a bit. I will try to find the other ones.