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Mars2501 [29]
4 years ago
10

A shop has 8 different types of postcards and at least 13 of each type. how many selections of 12 postcards are there if

Mathematics
1 answer:
Zolol [24]4 years ago
4 0

Answer:

Answered

Step-by-step explanation:

It is a combbinatorics problem. let's think as we need to do 8 partitions  

of these 13 to separate the postcards of different types. So The number of

partitions of n=13 into r=8 terms counting 0's as terms as  C(n+r-1,r-1)​.

(a)

Here n=13 and r=8, put it in the above formula so we get C(13+8-1,8-1)= C(20,7)= 77520 selections.

b).

Here, either (i) we can choose none of type I or (ii) we choose one of type I

Case(i): r=7, n=12 (Here we have only 7 types to choose from​)

Case(ii): r=7, n=11 (Here we have only 11 cards to choose and only 7 types to choose them from)​

Case (i) + Case(ii) = ,C(12+7-1,7-1) + C(11+7-1,7-1) = C(18,6) + (17,6) = 18564+12376 = 30940 selections.

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Step-by-step explanation:

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3 years ago
A random sample of 184 students at South High School were surveyed on whether they would prefer going to a movie or a concert. T
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The correct statements are as follows;

42% of the students prefer a concert over a movie.

A greater ratio of 11th graders prefer a concert to a movie

The difference in the percent of students who prefer a movie over a concert is 16%

Given that

A random sample of 184 students at South High School was surveyed on whether they would prefer going to a movie or a concert.

              10th   11th   12th   total

Movie       .18    .16     .24    .58

Concert     .15     .18     .09   .42

Total           .33     .34    .33    1

According to the question

The marginal relative frequency for 10th graders is 0.18.  

This is an incomplete statement.

The marginal frequency is a number, not a percent.

42% of the students prefer a concert over a movie.  

42% preferred a convert to the 58% who preferred a movie.  

This statement is True.

A greater ratio of 11th graders prefers a concert to a movie.

18/100 concert to 16/100 for the movie for 11th graders.

\rm = (0.58 -0.42) \times  100 \\\\ =0.16 \times 100\\\\= 16 \ percent

 More 12th graders were surveyed than any other grade level.

There were more 11th graders surveyed (34%) to (33%) for 12 graders False

The difference in the percent of students who prefer a movie over a concert is 16%.  

To know more about Probability click the link given below.

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4 0
3 years ago
Select all choices that describe rectangles with same area that are NOT congruent.
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B,E,F sorry if I’m wrong
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Answer:

The speed of the truck is 42 mph

Step-by-step explanation:

we know that

The speed is equal to divide the distance by the time

Let

s -----> the speed in miles per hour

d ----> the distance in miles

t ----> the time in hours

s=\frac{d}{t}

d=s(t)

step 1

Find out the distance traveled by the car at 7:00 P.M

we have

s=46\ \frac{mi}{h}

t=7:00 P.M-4:00 P.M=3\ h

d=s(t)

substitute the values

d=46(3)=138\ mi

step 2

Find out the speed of the truck

we know that

At 7:00 P.M the distance is equal to

d=264-138=126\ mi

t=7:00 P.M-4:00 P.M=3\ h

substitute

s=\frac{126}{3}

s=42\ \frac{mi}{h}

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