Answer: 4/25
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Explanation:
Let's define two events A and B
A = event of selecting red on the first draw
B = event of selecting red on the second draw
P(A) is the notation that means "probability of event A occurring"
P(A) = 2/5 because there are 2 red marbles out of 5 total (2 red + 3 black = 5)
Similarly, P(B) = 2/5 as well because A and B deal with the same color red, and because Abby put the first marble back
Multiply the probabilities
P(A and B) = P(A)*P(B) ... see note below
P(A and B) = (2/5)*(2/5)
P(A and B) = (2*2)/(5*5)
P(A and B) = 4/25 which is the answer
Note: the equation used is only valid if events A and B are independent, which they are in this case. The fact we put the marble back means the chances of picking red are the same as before.
The expression that is equivalent to 100n^2-1 is A. (10n)^2-(1)^2 because anything equates to 1 is 1
Answer:
im gonna guess 20 because 5x4=20
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
please mark brainliest thanks:)
Answer:
40 miles
Step-by-step explanation:
Let's set <em>x</em> to the number of miles driven, and <em>t</em> to the number of hours it took to drive.
We know that 40<em>t</em> is equal to <em>x</em>.
We also know that 40<em>t</em> is equal to 30(<em>t</em> + 1/3).
Solve for t:
40t = 30(t+1/3)
40t = 30t + 10
Subtract 30t from both sides:
10t = 10
Divide 10 from both sides:
t = 1
40t = 40 x 1 = 40 miles