Answer:
P ( blue ) = 1/4
P ( white ) = 5/12
P ( red ) = 1/3
P ( not red ) = 2/3
Step-by-step explanation:
To find the probability of a marble being chosen, it is the number of that color over the total
We need to find the total number of marbles
4 red+ 5 white+3 blue = 12 marbles
P ( blue ) = 3 blue / 12 total = 3/12 = 1/4
P ( white ) = 5 white / 12 total = 5/12
P ( red ) = 4 red/ 12 total = 4/12 = 1/3
How man marbles are not red
total marbles - red marbles = 12-4 = 8
8 marbles are not red
P ( not red ) = 8 not red / 12 total = 8/12 = 2/3
Given problem is 
To simplify that we need to multiply and divide by conjugate of the denominator
conjugate of denominator 6+i will be 6-i as we just need to change sign of the imaginary part
Now multiply and divide by 6-i
Hence final answer is 
Start by adding together the shortest two sides, 7 and 8.7 inches. Result: 15.7 inches. Because this sum is greater than the longest side, 15.4 inches, it's possible to construct a triangle, whose largest angle will be close to 180 degrees.
The answer is obviously {2}since there are NO EVEN PRIME NUMBERS, except for 2. So,there is only 1 element.
