We think that this is an interesting puzzle, which requires some thought "Outside the box" as it were.
You have two ropes and you know that each rope will take exactly one hour to burn completely. The bad news is that the rate of burn along the ropes is inconsistent; parts of them will burn more quickly and other parts will burn more slowly, and both ropes are different.
But you do know that the total burn time for both ropes is sixty minutes, even if you can't assume that when half of the length is burnt, 30 minutes have elapsed.
The challenge is to measure exactly three quarters of an hour (45 minutes) using these two ropes and as many matches as you want.
We’ll give the answer and explanation on Monday at 9.00 as usual.