Answer:
it saves 2.5 minutes
Step-by-step explanation:
The expected value of a random variable is the sum of products of possibilities and the probability of each.
Here, you have a probability of 0.9 of saving 5 minutes, and a probability of 0.1 of adding 20 minutes.
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The expected value of the shortcut is ...
0.9(-5) +0.1(20) = -4.5 +2.0 = -2.5
The shortcut is expected to save 2.5 minutes on average.
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<em>Additional comment</em>
The probability of 0.9 comes from the 9 of 10 trips that result in a time saving.
Answer:
x = 2
y = -3
Step-by-step explanation:
Step 1: Write systems of equation
8x + 7y = -5
x = -3y - 7
Step 2: Solve for <em>y</em>
- Substitute 2nd equation into 1st: 8(-3y - 7) + 7y = -5
- Distribute 8: -24y - 56 + 7y = -5
- Combine like terms: -17y - 56 = -5
- Add 56 to both sides: -17y = 51
- Divide both sides by -17: y = -3
Step 3: Solve for <em>x</em>
- Substitute <em>y</em> to find <em>x</em>: x = -3(-3) - 7
- Multiply: x = 9 - 7
- Subtract: x = 2
Step 4: Check
<em>Plug in x, y into an original equation to verify it's a solution.</em>
2 = -3(-3) - 7
2 = 9 - 7
2 = 2
1. Subtract 3x from both sides
2y = 18 - 3x
2. Divide both sides by 2
y = 18 - 3x/2
3. Factor out the common term 3
y = 3(6 - x)/2
Your answer for that question would be
D.AD=AB
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