I have two 20-sided dice that each have 4 maroon sides, 7 teal sides, 8 cyan sides, and one sparkly side. If I roll both dice, what is the probability they come up the same?
+23254 The only way that both can come up with maroon sides is for both to be maroon, which will occur 4/20 x 4/20 = 16/400 times.
Both teal: 7/20 x 7/20 = 49/400.
Both cyan: 8/20 x 8/20 = 64/400.
Both sparkly: 1/20 x 1/20 = 1/400.
In each of the above cases, the dice match, so add all the individual possibilities:
16/400 + 49/400 + 64/400 + 1/400 = 130/400
+23254 The only way that both can come up with maroon sides is for both to be maroon, which will occur 4/20 x 4/20 = 16/400 times.
Both teal: 7/20 x 7/20 = 49/400.
Both cyan: 8/20 x 8/20 = 64/400.
Both sparkly: 1/20 x 1/20 = 1/400.
In each of the above cases, the dice match, so add all the individual possibilities:
16/400 + 49/400 + 64/400 + 1/400 = 130/400
