Answer:
0.8
Step-by-step explanation:
We can solve P(A or B) by using the following:

Since we know P(A) = 0.6, P(B) = 0.3 and P(A and B) = 0.1 we obtain:

So for eliminating, you only solve for one variable first.
I solved for y, so I multiplied by -4 to eliminate the x.
Then I got y= -1
I then substituted that to one of the equations to get x.
Y=12 because the triangles have proportional side lengths
Let's assume the number be x.
So, sum of a number and 10 can be written as x+10.
Now the given statement is "One half of the sum of a number and 10 ".
So, one half of x+10 can be written as 
Answer:
a = 3, b = -1, c = 10
Step-by-step explanation:
Let the three numbers be a, b and c.
Equation 1: a + b + c = 12
Equation 2: a + 2b + 3c = 31
Equation 3: 9b + c = 1
Equation 2 - Equation 1:
Equation 4: b + 2c = 19
Equation 3 times by the number 2
Equation 5: 18b + 2c = 2
Equation 5 - Equation 4
17b = -17
b = -1
Substitute into Equation 4:
2c - 1 = 19
2c = 20
c = 10
Substitute into Equation 1:
a + b + c = 12
a - 1 + 10 = 12
a = 3