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aleksandr82 [10.1K]
3 years ago
13

Suppose that 21 girls and 21 boys enter a mathemat- ics competition. furthermore, suppose that each entrant solves at most six q

uestions, and for every boy-girl pair, there is at least one question that they both solved. show that there is a question that was solved by at least three girls and at least three boys.

Mathematics
1 answer:
Stolb23 [73]3 years ago
7 0

Individuals shall draw a table consisting of 21 boys in each column and 21 girls in each row as shown on the image below.

The table will have 21x21 = 441 boxes. Mark each box with a letter showing the problem solved by both that boy and girl. Since at least one problem was solved by a girl and a boy, therefore each box will have a letter. Each entrant solved at most six questions, so there can be at most six letters in any row or column. This means six different letters can be there in a row only if at least 11 of the boxes contain letters appearing three or more times in the row. Individuals go through each row and color all the boxes, say blue. Therefore, 11 boxes in each row must be colored blue.

The number of the boxes that must be colored blue = 21 x 11 = 231. Individuals can apply the same process to the columns and color at least 231 boxes, say green. But the total boxes are 441 only. Therefore, by Pigeonhole principle, there will be some boxes which will be both blue and green. The problem of doubly colored boxes represents a problem solved by at least three boys and three girls.

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  $1769.06

Step-by-step explanation:

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so the average is ...

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Her pension is then ...

  0.01875 × $94,350 = $1769.06

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<em>Additional comment</em>

This is equivalent to the total of those salaries, divided by 160.

  T/3 × 0.01875 = T × (0.01875/3) = T × 0.00625 = T/160

Sometimes, there are simpler ways to calculate things like this.

8 0
3 years ago
In the science club, 1/2 the students are freshman, 1/20 are sophomores, 1/10 are juniors, and 70 students are seniors. How many
Nataly [62]

So we are using the denominator 20.

1/2 of 20 would be 10.

So, out of 20 we multiply it by 10 since it is our numerator.

Now, we have converted it to 100/200.

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6 0
3 years ago
Which of the following sets of ordered pairs represents a function?
scZoUnD [109]

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6 0
2 years ago
Read 2 more answers
Peter is planting a rectangular garden. The length is 15 yards longer than the width. Jorge is planting a square garden. The sid
const2013 [10]

If the width of peter's garden is 32 yards, the ratio of the areas is 47: 32

<h3>Area of a rectangle.</h3>

area of rectangle = lw

where

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Therefore,

Peter rectangular garden

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Jorge is planting a square garden. The sides of Jorge's garden are equal to the width of Peter's garden.

Therefore,

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The ratios are as follows;

(15 + x)x : x²

Therefore, if the width of peter's garden is 32 yards, the ratio of the areas is as follows:

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1504: 1024

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7 0
2 years ago
It's a little blurry sorry please help
Ghella [55]

<u>Answer:</u>

It's X=2

<u>Working out:</u>

<u>(left one):</u>

2(x+3)=10

2x+6=10

2x=10-6

2x=4

x=2

Working out:

(right one):

2(x+3) must be all divided by 2 so it will be x+3 and same for 10, it will be 5 so...

x+3=5

x=5-3

x=2

Hope it helps ^---^

3 0
2 years ago
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