Answer:
8 / 15
Step-by-step explanation:
Sample space = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
Required outcome :
Even numbers = (2, 4, 6, 8, 10, 12, 14) or 13
Total required outcomes = 8
Probability = required outcome / Total possible outcomes
P(even number or 13) = 8 / 15
Vertex form formula: y = a(x-h)^2 +k, with vertex (h,k)
There are multiple ways to find the vertex. One way is to find the roots and then find the x value exactly in between them, because this parabola is symmetrical.
0 = (x - 3)(x + 2), so x = 3 and -2. The point directly in the middle is x = 1/2 = h
To find the y value of the vertex, plug in 1/2 to the equation.
(1/2)^2 - 2(1/2) + 5 = 4.25 = k
y = (x - 0.5)^2 + 4.25
Answer:
A) there are 13 cards per suit and 4 suits, a total of 52 cards. So there are 13*2=26 red cards in a deck of 13*4=52, the odds of drawing a red card are 26/52=1/2=50%
B) Again outside knowledge is required, you name four suits but not their colors. Nonetheless, unless this is a very unusual deck, the diamonds and hearts are red, spades and clubs black. So that’s 2 red suits out of 4 suits. 2/4=1/2=50%
C) there are 2 black suits and 2 red suits. The odds of getting a red card are 2/(2+2)=2/4=1/2 or 50%
Each of those answers is a different way to figure the odds, they come out the same each time, as expected.
However, what if we assume that you mean… when drawing a 5 card poker hand? Or when Penn Jillette asks you “is this your card?”+ Or if you draw every card in the deck? Or if you are playing some macabre game in which you die if you draw the ace of spades but you may only stop drawing if you draw a red card?
There are myriad possible meanings to your question, I’ve just made the simplest assumption and given the odds on that… but my answer is woefully incomplete.
+ Hint, when Penn Jillette asks you “is this your card” your card is always the 3 of clubs. So… 0% chance.
