Help pleaseee i am awful at math

A florist has to choose four different types of flowers to include in a bouquet. In how many ways can the florist do this, if th

Nat2105 [25]

Answer:

Step-by-step explanation:

Given:

Type of Flowers = 5

To choose = 4

Required

Number of ways 4 can be chosen

The first flower can be chosen in 5 ways

The second flower can be chosen in 4 ways

The third flower can be chosen in 3 ways

The fourth flower can be chosen in 2 ways

Total Number of Selection = 5 * 4 * 3 * 2

Total Number of Selection = 120 ways;

Alternatively, this can be solved using concept of Permutation;

Given that 4 flowers to be chosen from 5,

then n = 5 and r = 4

Such that

$nPr = \frac{n!}{(n - r)!}$

Substitute 5 for n and 4 for r

$5P4 = \frac{5!}{(5 - 4)!}$

$5P4 = \frac{5!}{1!}$

$5P4 = \frac{5*4*3*2*1}{1}$

$5P4 = \frac{120}{1}$

$5P4 = 120$

Hence, the number of ways the florist can chose 4 flowers from 5 is 120 ways

4 0

3 years ago

Eights rooks are placed randomly on a chess board. What is the probability that none of the rooks can capture any of the other r

erastova [34]

Answer:

The probability is $\frac{56!}{64!}$

Step-by-step explanation:

We can divide the amount of favourable cases by the total amount of cases.

The total amount of cases is the total amount of ways to put 8 rooks on a chessboard. Since a chessboard has 64 squares, this number is the combinatorial number of 64 with 8, $64 \choose 8 .$

For a favourable case, you need one rook on each column, and for each column the correspondent rook should be in a diferent row than the rest of the rooks. A favourable case can be represented by a bijective function $f : A \rightarrow A ,$ with A = {1,2,3,4,5,6,7,8}. f(i) = j represents that the rook located in the column i is located in the row j.

Thus, the total of favourable cases is equal to the total amount of bijective functions between a set of 8 elements. This amount is 8!, because we have 8 possibilities for the first column, 7 for the second one, 6 on the third one, and so on.

We can conclude that the probability for 8 rooks not being able to capture themselves is

$\frac{8!}{64 \choose 8} = \frac{8!}{\frac{64!}{8!56!}} = \frac{56!}{64!}$

7 0

2 years ago

Please answer soon (40 Points)

Aleonysh [2.5K]

Answer:

-99g - 54

Step-by-step explanation:

-9*11g = -99g

-9*6= -54

So, it is -99g - 54

Hope this helps!

4 0

1 year ago

The time taken to deliver a pizza has a uniform probability distribution from 20 minutes to 60 minutes. What is the probability

Whitepunk [10]

Answer:

(1) The probability that the time to deliver a pizza is at least 32 minutes is 0.70.

(2a) The percentage of results more than 45 is 79.67%.

(2b) The percentage of results less than 85 is 91.77%.

(2c) The percentage of results are between 75 and 90 is 15.58%.

(2d) The percentage of results outside the healthy range 20 to 100 is 2.64%.

Step-by-step explanation:

(1)

Let Y = the time taken to deliver a pizza.

The random variable Y follows a Uniform distribution, U (20, 60).

The probability distribution function of a Uniform distribution is:

$f(x)=\left \{ {{\frac{1}{b-a};\ x\in [a, b] } \atop {0};\ otherwise} \right.$

Compute the probability that the time to deliver a pizza is at least 32 minutes as follows:

$P(Y\geq 32)=\int\limits^{60}_{32} {\frac{1}{b-a} } \, dx \\=\frac{1}{60-20} \int\limits^{60}_{32} {1 } \, dx\\=\frac{1}{40}\times[x]^{60}_{32}\\=\frac{1}{40}\times[60-32]\\=0.70$