Answer:
Step-by-step explanation:
If the new fraction is 8/12 I will show how to find it.
Let's say the original denominator is x, then the numerator is x-4, so we have (x-4)/x.
Then it says f we add 4 to both, so now we have x/(x+4) this equals 8/12. Now, keep in mind -4 cannot be an answer because it would make x/(x+4) be divided by 0 which wouldn't exist.
Now we just use algebra.
x/(x+4) = 8/12
12x = 8(x+4)
12x = 8x + 32
4x = 32
x = 8
So the original fraction (x-4)/x = (8-4)/8 = 4/8
250 divided by 10 squared is 2.5
X - the first numberx + 13 - the second number
The equation:
x + x + 13 = 152x + 13 = 15 |-132x = 2 |:2x = 1
x + 13 = 1 + 13 = 14
Answer: 1 and 14
Answer:
Fast ball challenge
Step-by-step explanation:
Given
Slow Ball Challenge
![Pitches = 7](https://tex.z-dn.net/?f=Pitches%20%3D%207)
![P(Hit) = 80\%](https://tex.z-dn.net/?f=P%28Hit%29%20%3D%2080%5C%25)
![Win = \$60](https://tex.z-dn.net/?f=Win%20%3D%20%5C%2460)
![Lost = \$10](https://tex.z-dn.net/?f=Lost%20%3D%20%5C%2410)
Fast Ball Challenge
![Pitches = 3](https://tex.z-dn.net/?f=Pitches%20%3D%203)
![P(Hit) = 70\%](https://tex.z-dn.net/?f=P%28Hit%29%20%3D%2070%5C%25)
![Win = \$60](https://tex.z-dn.net/?f=Win%20%3D%20%5C%2460)
![Lost = \$10](https://tex.z-dn.net/?f=Lost%20%3D%20%5C%2410)
Required
Which should he choose?
To do this, we simply calculate the expected earnings of both.
Considering the slow ball challenge
First, we calculate the binomial probability that he hits all 7 pitches
![P(x) =^nC_x * p^x * (1 - p)^{n - x}](https://tex.z-dn.net/?f=P%28x%29%20%3D%5EnC_x%20%2A%20p%5Ex%20%2A%20%281%20-%20p%29%5E%7Bn%20-%20x%7D)
Where
--- pitches
--- all hits
--- probability of hit
So, we have:
![P(x) =^nC_x * p^x * (1 - p)^{n - x}](https://tex.z-dn.net/?f=P%28x%29%20%3D%5EnC_x%20%2A%20p%5Ex%20%2A%20%281%20-%20p%29%5E%7Bn%20-%20x%7D)
![P(7) =^7C_7 * 0.80^7 * (1 - 0.80)^{7 - 7}](https://tex.z-dn.net/?f=P%287%29%20%3D%5E7C_7%20%2A%200.80%5E7%20%2A%20%281%20-%200.80%29%5E%7B7%20-%207%7D)
![P(7) =1 * 0.80^7 * (1 - 0.80)^0](https://tex.z-dn.net/?f=P%287%29%20%3D1%20%2A%200.80%5E7%20%2A%20%281%20-%200.80%29%5E0)
![P(7) =1 * 0.80^7 * 0.20^0](https://tex.z-dn.net/?f=P%287%29%20%3D1%20%2A%200.80%5E7%20%2A%200.20%5E0)
Using a calculator:
--- This is the probability that he wins
i.e.
![P(Win) =0.2097152](https://tex.z-dn.net/?f=P%28Win%29%20%3D0.2097152)
The probability that he lose is:
---- Complement rule
![P(Lose) = 1 -0.2097152](https://tex.z-dn.net/?f=P%28Lose%29%20%3D%201%20-0.2097152)
![P(Lose) = 0.7902848](https://tex.z-dn.net/?f=P%28Lose%29%20%3D%200.7902848)
The expected value is then calculated as:
![Expected = P(Win) * Win + P(Lose) * Lose](https://tex.z-dn.net/?f=Expected%20%3D%20P%28Win%29%20%2A%20Win%20%2B%20P%28Lose%29%20%2A%20Lose)
![Expected = 0.2097152 * \$60 + 0.7902848 * \$10](https://tex.z-dn.net/?f=Expected%20%3D%200.2097152%20%2A%20%5C%2460%20%2B%200.7902848%20%2A%20%5C%2410)
Using a calculator, we have:
Considering the fast ball challenge
First, we calculate the binomial probability that he hits all 3 pitches
![P(x) =^nC_x * p^x * (1 - p)^{n - x}](https://tex.z-dn.net/?f=P%28x%29%20%3D%5EnC_x%20%2A%20p%5Ex%20%2A%20%281%20-%20p%29%5E%7Bn%20-%20x%7D)
Where
--- pitches
--- all hits
--- probability of hit
So, we have:
![P(3) =^3C_3 * 0.70^3 * (1 - 0.70)^{3 - 3}](https://tex.z-dn.net/?f=P%283%29%20%3D%5E3C_3%20%2A%200.70%5E3%20%2A%20%281%20-%200.70%29%5E%7B3%20-%203%7D)
![P(3) =1 * 0.70^3 * (1 - 0.70)^0](https://tex.z-dn.net/?f=P%283%29%20%3D1%20%2A%200.70%5E3%20%2A%20%281%20-%200.70%29%5E0)
![P(3) =1 * 0.70^3 * 0.30^0](https://tex.z-dn.net/?f=P%283%29%20%3D1%20%2A%200.70%5E3%20%2A%200.30%5E0)
Using a calculator:
--- This is the probability that he wins
i.e.
![P(Win) =0.343](https://tex.z-dn.net/?f=P%28Win%29%20%3D0.343)
The probability that he lose is:
---- Complement rule
![P(Lose) = 1 - 0.343](https://tex.z-dn.net/?f=P%28Lose%29%20%3D%201%20-%200.343)
![P(Lose) = 0.657](https://tex.z-dn.net/?f=P%28Lose%29%20%3D%200.657)
The expected value is then calculated as:
![Expected = P(Win) * Win + P(Lose) * Lose](https://tex.z-dn.net/?f=Expected%20%3D%20P%28Win%29%20%2A%20Win%20%2B%20P%28Lose%29%20%2A%20Lose)
![Expected = 0.343 * \$60 + 0.657 * \$10](https://tex.z-dn.net/?f=Expected%20%3D%200.343%20%2A%20%5C%2460%20%2B%200.657%20%2A%20%5C%2410)
Using a calculator, we have:
![Expected = \$27.15](https://tex.z-dn.net/?f=Expected%20%3D%20%5C%2427.15)
So, we have:
-- Slow ball
--- Fast ball
<em>The expected earnings of the fast ball challenge is greater than that of the slow ball. Hence, he should choose the fast ball challenge.</em>