A fair, twenty-faced die has 19 of its faces numbered from 1 through 19 and has one blank face. Another fair, twenty-faced die has of its faces numbered from 1 through 8 and10 through 20 and has one blank face. When the two dice are rolled, what is the probability that the sum of the two numbers facing up will be 36. Express your answer as a common fraction.
if the sum of the two numbers are 36, then we can have
Dice 1 rolls | dice 2 rolls
16 |20
17 |19
18 |18
19 |17
so there are 4 ways.
now the total number of sums possible(if you consider the blank faces numbers)is 20x20=400 possible solutions, so the answer would be 4/400=$\boxed{1/100}$
although if the blank faces are not considered numbers then the total number of possible sums would be 19x19=361, so the answer would be $\boxed{4/361}$