Rafael will also give 50 tokens to the first person who posts the correct solution to the following problem:
One spider that live in the forest is trying to spin a really big net from one three to another. The first day the spider make one little square of the net. The work he do one day is the next double, and so on the spider will spend 30 days making the net. How many days will the work last if he call her sister in order to help her?
P.S. The sister will work at the same rythm.
:doubt: =D>