1/216 is the simplest, but <span>0.00462962962 is more precise.</span>
Just add to find X
20 + 60 = 80
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X = 80
To make sure plug it in
80 - 60 = 20
The equation is true
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x = 80 is your answer
Solution
The table below is the required sample space of the to fair die
From the above table
The sample space contain 36 outcomes
Event A: The sum is greater than 9
we will look at the table and count all the elements that are greater than 9
There are 6 elements (they are 10, 10, 10, 11, 11, 12 from the table)
The probability for event A will be

P(A) = 1/6
Event B: The sum is an even number.
We will look at the table and count the number of elements that are even
There are 18 elements (notice that there are 3 even number on each of the 6 rows of the table)
The probability for event B will be

p(B) = 1/2
The first option :
Multiply the first equation by 8 and the second equation by 2
would not result in the elimination of the variables in this system