Help!

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 24.  Express your answer as a common fraction.

 

+24	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	blank
1
2
3
4
5																			yes1
6																		yes2
7																	yes3
8																yes4
10														yes5
11													yes6
12												yes 7
13											yes8
14										yes9
15									yes10
16								yes 11
17							yes 12
18						yes 13
19					yes 14
20				yes 15
blank

 

 

P(sum is 24)= 15/(20*20) = 15/400 = 3 /80