>Let each fuse burn for 15 minutes and extinguish them. The rest of each fuse will burn for 45 minutes.
>
>>You have two fuses of variable lengths.
>>
>>Each fuse burns for exactly 1 hour.
>>
>>Each fuse burns unevenly. ( example 1/10th of the fuse could burn for 50 minutes and the rest of the fuse could take 10 minutes. ) You don't know until after the fuse has burned up.
>>
>>Make the two fuses last exactly 45 minutes.

You don't have a watch or any other way of telling time. How can you determine when 15 minutes is up?