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Goshia [24]
2 years ago
6

a student played a computer game 500 times and won 370 of these game. he then won the next "x" games and lost none. he has now w

on 75% of fhe games he has played. find the value of "x"
Mathematics
1 answer:
a_sh-v [17]2 years ago
3 0

So, this is a proportion problem. If we express 75% as a fraction (3/4ths), we have:

\frac{370+x}{500+x}=\frac{3}{4}

Since he won all of his games, we add the number won (x), to the number previously won and divide it by the total games played which is just the previous games played plus the number of current games played, so since he lost no games we still add x to the denominator as well. Solving this gives us:

4(370+x)=3(500+x) \implies\\ 1480+4x=1500+3x \implies \\ x=20

That x value is 20.

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Parallel, orthogonal, or neither.
zzz [600]
Vectors are orthogonal, when dot product u\cdot v=0

u\cdot v=\langle-1,3\rangle\cdot\langle-9,-3\rangle=(-1)\cdot(-9)+3\cdot(-3)=9-9=0

Vectors u and v are orthogonal.
8 0
3 years ago
4. In a sample of 1000 people, 130 can wiggle their ears. Two unrelated people are
Elina [12.6K]

Using the hypergeometric distribution, it is found that there is a 0.7568 = 75.68% probability that neither can wiggle his or her ears.

The people are chosen from the sample without replacement, which is why the <u>hypergeometric distribution</u> is used to solve this question.

Hypergeometric distribution:

P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}

C_{n,x} = \frac{n!}{x!(n-x)!}

The parameters are:

  • x is the number of successes.
  • N is the size of the population.
  • n is the size of the sample.
  • k is the total number of desired outcomes.

In this problem:

  • 1000 people means that N = 1000
  • 130 can wiggle their ears, thus k = 130
  • Two are selected, thus n = 2.

The probability that neither can wiggle his or her ears is P(X = 0), thus:

P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}

P(X = x) = h(0,1000,2,130) = \frac{C_{130,0}C_{870,2}}{C_{1000,2}} = 0.7568

0.7568 = 75.68% probability that neither can wiggle his or her ears.

A similar problem is given at brainly.com/question/24826394

5 0
2 years ago
Six classrooms lost electricity this morning for 47 minutes. Determine the percent of an hour that the classrooms were without e
meriva
They were without electricity for 47 minutes.....determine the percent of an hr....so 1 hr = 60 minutes.....so they were out 47 out of 60 minutes...
47/60 = 0.783 = 78.3%.....so just type in 78.3 because ur not supposed to include the percent sign
8 0
3 years ago
18 points
bearhunter [10]
12 is first one 7 is 2nd one 9 is the last one
4 0
3 years ago
Find the side length of the square
IgorLugansk [536]

the answer is 30.3

hope it helps

8 0
3 years ago
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