Roberto i have cautioned you before about your gambling, we had a gambling topic on here for the shortest space of time and it did not last, I don't think it should be encouraged this way. : )
If thrown together then the odds are all the same. However, if each dice is thrown separately the odds will alter considerably although the law of probability will be the same.
I.e if you throw two 6's, nobody will offer you 5 to 1 in throwing a six in 16 throws. Likewise if you throw 15 dice with no 6's the odds of throwing a treble 6 will be about 108 to 1.
im guessing your grammer wasnt up to scratch katie but then i wouldn't know as i skipped a level english class for 6 months bought a study aid on chaucer wrote a load of waffle in my exam and got a b :)