You have a lighter and a number of long fuses, of which you only know that they burn for exactly one hour after you lighted them at one end. However, you do not know whether they burn with constant speed, so the first half of the fuse can be burnt in only ten minutes while the rest takes the other fifty minutes to burn completely.

The question: How can you measure exactly three quarters of an hour with these fuses?

A hint : Click here!

A second hint : Click here!

The answer: Click here!