This is a variation of a well known puzzle, you can find the other versions on PSE.
You have three ropes and a box with ten matches. As usual each rope takes one hour to burn completely when lighted from any end but it does not burn uniformly. This means (for example) that it could take five minutes to burn the first half and then 55 minutes to burn the remaining half. Or it could take 40 minutes for the first half and 20 for the second, you don't know. Each half does not burn uniformly too and the three ropes are different.
Every match lasts 5 seconds, so you have enough time to burn one or more ends of one or more ropes with the same match.
How do you measure exactly 1 hour and 8 minutes?