Let x represent the number of liters of 50% acid Theresa puts into the mix. The the number of liters of 30% acid will be (420-x). The total amount of acid in the final solution will be ...
0.50x + 0.30(420-x) = 0.45(420)
0.20x + 126 = 189 . . . . . . . . . . . . . . . simplify
0.20x = 63 . . . . . . . . . . . . . . . . . . . . . subtract 126
x = 63/0.20 = 315 . . . . . . . . . . . . . . . liters of 50% solution
(420-x) = 420-315 = 105 . . . . . . . . . liters of 30% solution
Theresa should mix ...
105 liters of 30% solution
315 liters of 50% solution
So chance to get a black pen: 4/10=2/5
Chance to get a red pen: 1/10
Chance for the two happened at the same time
2/5 * 1/10 = 2/50=1/25
I think... I’m not very sure though

= -2 with a exponent six
Well Exponents mean that you multiply the number 6 times.
Soo..

= -2 x -2 x -2 x -2 x -2 x -2 = 64
So <span>
= 64 </span>
Good Luck! :)
Answer:
A. 35.69%
B. 62.77%
Step-by-step explanation:
In this case, what we must do is calculate the probability supported with the data in the table.
Part A.
What is the probability that a randomly selected student is a 7th grader?
Here the total is all the students that would be the sum of all the grades, which are 325 students.
the number of 7th graders is 116, so the probability is:
116/325 = 0.3569
that is, 35.69%
Part B: What percentage of the students interviewed play Video games?
The total number of students is the same 325 and of those 204 play video games, therefore:
204/325 = 0.6277
that is, 62.77%