5/7 = x/42
5/1 = x/6
X = 30
2/5
Since 12 out of 30 marbles were black, you can assume that the percentage of black marbles in the bag is 40% (Ex: 12/30=.4) The probability that the marble you pick is black is equal to the percentage of black marbles in the bag. 40% is equal to 2/5.
Answer: 0.375
Step-by-step explanation:
Hey there! If you have any questions feel free to leave them in the comments below.
To find the answer you would divide the numerator by the denominator. 
would be equal to 0.375
~I hope I helped you :)~
We know that the area of a circle in terms of π will be πr². However the area with respect to the diameter will be a different story. The first step here is to find a function relating the area and diameter of any circle --- ( 1 )
For any circle the diameter is 2 times the radius,
d = 2r
Therefore r = d / 2, which gives us the following formula through substitution.
A = π(d / 2)² = πd² / 4
<u>Hence the area of a circle as the function of it's diameter is A = πd² / 4. You can also say f(d) = πd² / 4.</u>
Now we can substitute " d " as 4, solving for the area ( A ) or f(4) --- ( 2 )
f(4) = π(4)² / 4 = 16π / 4 = 4π - <u>This makes the area of circle present with a diameter of 4 inches, 4π.</u>
