Billy has a gift card with a $160 balance. He buys several video games that cost $40 each. After the purchases, his gift card ba
2 answers:
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Answer:
The standard deviation of this probability distribution is 1.2.
Step-by-step explanation:
We have that:
P(X = 0) = 0.25
P(X = 1) = 0.3
P(X = 2) = 0.1
P(X = 3) = 0.35
Mean:
Each value multiplied by its probability. So
Variance:
Sum of the squares of the values subtracted from the mean, and multiplied by its probability.
Standard deviation:
Square root of the variance. So
The standard deviation of this probability distribution is 1.2.
Answer: -3 and 5
<u>Step-by-step explanation:</u>
Let x represent the 1st digit and y represent the 2nd digit. Then,
Eq 1: 2x + 3y = 9 → 3(2x + 3y = 9) → 6x + 9y = 27
Eq 2: 3x + 2y = 1 → -2(3x + 2y = 1) → <u>-6x - 4y = -2</u>
5y = 25
y = 5
Substitute y = 5 into either of the original equations to solve for x:
2x + 3y = 9
2x + 3(5) = 9
2x + 15 = 9
2x = -6
x = -3
Check (using the other original equation):
3x + 2y = 1
3(-3) + 2(5) = 1
-9 + 10 = 1
-1 = 1