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:
2673
Step-by-step explanation:
-2x cube + 2x cube makes 0, so u can delete it,
then 6x + 10x makes 16x,
so the final answer should be 16x+7xtothepower4
Step 
<u>Find the length of the side MN</u>
we know that
Applying the Pythagorean Theorem

Solve for MN

in this problem

Substitute in the formula above



Step 
<u>Find the value of cos (M)</u>
we know that
in the right triangle MNL


Substitute



therefore
The answer is
The value of cos(M) is equal to 
Given that the concentration has been modeled by the formula:
C(t)=50t/(t^2+25)
where:
t is time in hours.
The concentration after 5 hours will be given by:
t= 5 hours
plugging the value in the equation we get:
C(5)=(50(5))/(5^2+25)
simplifying the above we get:
C(5)=250/(50)=5 mg/dl
Answer: 5 mg/dl