Answer: a) P = 0.5, b) P = 0.07
Step-by-step explanation:
Hi!
Lets call X₁ the time at which you arrive, and X₂ the time at which Bob arrives. Both are random variables with uniform density in the interval [0, 60] (in minutes). Their joint distribuition is uniform over the square in the image, with value P = 1/(60*60) = 1/3600.
a) For you to get more cake than Bob, you should arrive earlier. This event is A = { X₁ < X₂ }, the shaded triangle in the figure.The area of this event (set) is half the total area of the square, so P(A) = 0.5.
It makes sense, beacuse its equally probable for you or Bob to arrive earlier, as both have uniform density over the time interval.
b) In this case you arrive later than Bob, but less than 5 minutes later. So the event is B = { X₂ < X₁ < (X₂ + 5) } . This is the gray shaded area in b) part of the image. Its area is the difference two triangles (half square - blue triangle), then the probability is:
![P(B) = 0.5 - \frac{(0.5*55^2)}{3600} =0.07](https://tex.z-dn.net/?f=P%28B%29%20%3D%200.5%20-%20%5Cfrac%7B%280.5%2A55%5E2%29%7D%7B3600%7D%20%3D0.07)
Answer:
$11 and $16
Step-by-step explanation:
let x be the cost of a student ticket then an adult ticket is x + 5 , then
3x + 7(x + 5) = 145 , that is
3x + 7x + 35 = 145
10x + 35 = 145 ( subtract 35 from both sides )
10x = 110 ( divide both sides by 10 )
x = 11
Student ticket costs $11 and adult ticket = x + 5 = 11 + 5 = $16
Answer:
In order, c= 3, x= -4, x= 2, m= 8, x= 25
Step-by-step explanation:
These are the answers. use pemdas for the distributive properties.
<h3>Answer:</h3>
- ABDC = 6 in²
- AABD = 8 in²
- AABC = 14 in²
<h3>Explanation:</h3>
A diagram can be helpful.
When triangles have the same altitude, their areas are proportional to their base lengths.
The altitude from D to line BC is the same for triangles BDC and EDC. The base lengths of these triangles have the ratio ...
... BC : EC = (1+5) : 5 = 6 : 5
so ABDC will be 6/5 times AEDC.
... ABDC = (6/5)×(5 in²)
... ABDC = 6 in²
_____
The altitude from B to line AC is the same for triangles BDC and BDA, so their areas are proportional to their base lengths. That is ...
... AABD : ABDC = AD : DC = 4 : 3
so AABD will be 4/3 times ABDC.
... AABD = (4/3)×(6 in²)
... AABD = 8 in²
_____
Of course, AABC is the sum of the areas of the triangles that make it up:
... AABC = AABD + ABDC = 8 in² + 6 in²
... AABC = 14 in²
Answer:
Positive discriminant = 2 real solution
x= -5,-40
Step-by-step explanation:
The discriminant is used to see how many solutions an equation has. If it is negative, the equation has no real solutions, if =0 the equation has 1, and if it is positive, the equation has two real solutions.
The discriminant is the part of the quadratic formula inside the square root:
![b^{2}-4ac](https://tex.z-dn.net/?f=b%5E%7B2%7D-4ac)
Every quadratic formula has the structure:
![ax^{2} +bx+c=0](https://tex.z-dn.net/?f=ax%5E%7B2%7D%20%2Bbx%2Bc%3D0)
So first, in order to meet this structure we need to add 200 to both sides so the equation is equal to 0. This gives us:
![x^{2} +45x+200=0](https://tex.z-dn.net/?f=x%5E%7B2%7D%20%2B45x%2B200%3D0)
Our a=1, b=45 and c=200
Now we can substitute these values into the discriminant:
![(45)^{2} -4(1)(200)](https://tex.z-dn.net/?f=%2845%29%5E%7B2%7D%20-4%281%29%28200%29)
Solve:
![2025-800=1225](https://tex.z-dn.net/?f=2025-800%3D1225)
The discriminant is a positive number which means this equation will have 2 real solution. Now we just need to plug in our values into the quadratic formula to solve this equation. Quadratic formula:
![x=\frac{-+/-\sqrt{b^{2}-4ac} }{2a} \\x=\frac{-45+/-\sqrt{1225} }{2}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-%2B%2F-%5Csqrt%7Bb%5E%7B2%7D-4ac%7D%20%7D%7B2a%7D%20%5C%5Cx%3D%5Cfrac%7B-45%2B%2F-%5Csqrt%7B1225%7D%20%7D%7B2%7D)
(Same discriminant value)
![x=\frac{-45+/-35}{2}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-45%2B%2F-35%7D%7B2%7D)
Now to find the two solutions, we use both signs in the equation. Solution 1:
![x=\frac{-45+35}{2}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-45%2B35%7D%7B2%7D)
![x=\frac{-10}{2}=-5](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-10%7D%7B2%7D%3D-5)
Our first solution is -5, now for the second:
![x=\frac{-45-35}{2}\\\\ x=\frac{-80}{2}=-40](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-45-35%7D%7B2%7D%5C%5C%5C%5C%20x%3D%5Cfrac%7B-80%7D%7B2%7D%3D-40)
The two solution to this equation are -5 and -40.
Hope this helped!