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4 years ago

How to solve this question? Please help me

Mathematics

1 answer:

Maurinko [17]4 years ago

8 0

Answer:

≈ 82 feet

Step-by-step explanation:

Since the triangle is right use Pythagoras' identity to calculate distance (d)

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides.

Here the hypotenuse is the distance (d) between the 2 poles, hence

d² = 80² + 45² = 6400 + 2025 = 8425 ( take the square root of both sides )

d = $\sqrt{8425}$ ≈ 82 feet ( to the nearest foot )

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What is the sum of 1/12 plus 3/8 in a fraction? A.1/6 B.1/5 C.11/48 D.11/24

Nuetrik [128]

D.11/24
1/12=2/24
3/8=9/24
2/24+9/24=11/24

6 0

3 years ago

Read 2 more answers

there are n counters in a bag. 4 of the counters are red and the rest are blue. Ross takes a counter from the bag at random and

Ainat [17]

Answer: n = 10.

Step-by-step explanation:

In the bag, we have n counters.

4 of the counters are red.

the rest are blue, then we have:

(n - 4) blue counters.

Now, the probability that Ross takes a blue counter from the bag is equal to the quotient between the number of blue counters (n - 4) and the total number of counters, n

Then the probability is:

p1 = (n - 4)/n

Now he draws another, and it must be blue again, then we can calculate the probability in the same way as above, but he already take a blue counter, so the number of blue counters is (n - 5) and the total number of counters is (n - 1)

The probability of this event is:

p2 = (n - 5)/(n - 1)

The joint probability (the probability that Ross takes two blue counters) is equal to the product of the individual probabilities, and we know that this is equal to 1/3, then we have the equation:

1/3 = ( (n - 4)/n)*((n - 5)/(n - 1))

Now let's solve this for n.

n*(n - 1)/3 = (n - 4)*(n - 5)

(n^2 - n)/3 = n^2 - 4*n - 5*n + 20

n^2 - n = 3*(n^2 - 9*n + 20)

n^2 - n = 3*n^2 - 27*n + 60

0 = (3*n^2 - n^2) - 27*n + n + 60

0 = 2*n^2 - 26*n + 60

The two solutions of this equation can be found with Bhaskara's equation:

$n = \frac{-(-26) +- \sqrt{(-26)^2 - 4*2*60} }{2*2} = \frac{26+- 14}{4}$

Then the two solutions are:

n = (26 - 14)/4 = 3

This is not an option, because we know for sure that we have 4 red counters, then this option can be discarded.

The other solution is:

n = (26 + 14)/4 = 40/4 = 10

Then we have n = 10, 10 counters in total.

4 0

3 years ago

3/5 of the class were boys. The teacher divided the boys equally into groups so the each group of boys had 1/10 of the number of

Lana71 [14]

I think boys =18
girls=12
boys :x
girls:y
student:z
the number of group for the boys :n
the numberof group for the girls :m
so x=(3/5)*z
y=(2/5)* z
x/y=3/2
3y-2x=0
(1/10)*z*n=(3/5) *z
so n=6
(1/5)*z*m=(2/5)* z
put x=(1/10)*z*6
y=(1/5)*z*2
into 3y-2x=0 and z=30
z=30 so x=(1/10)*30*6=18
y=(1/5)*30*2=12

4 0

3 years ago

The probability a person has read a book in the past year is 0.81. The probability a person is considered a millennial is 0.28.

ycow [4]

Answer:

(a) P(Millennial | Read a Book) = 0.3086

(b) P( Not Millennial | Did Not Read a Book) = 0.8421

(c)

P(Millennial and Read a Book) = P(Read a Book) × P(Millennial)

0.25 = 0.81 × 0.28

0.25 ≠ 0.2268

Since the relation doesn't hold true, therefore, being considered a millennial and having read a book in the past year are not independent events.

Step-by-step explanation:

The probability a person has read a book in the past year is 0.81.

P(Read a Book) = 0.81

The probability a person is considered a millennial is 0.28.

P(Millennial) = 0.28

The probability a person has read a book in the past year and is considered a millennial is 0.25.

P(Millennial and Read a Book) = 0.25

(a) Find P(Millennial | Read a Book)

Recall that Multiplicative law of probability is given by

P(A ∩ B) = P(B | A) × P(A)

P(B | A) = P(A ∩ B) / P(A)

For the given case,

P(Millennial | Read a Book) = P(Millennial and Read a Book) / P(Read a Book)

P(Millennial | Read a Book) = 0.25 / 0.81

P(Millennial | Read a Book) = 0.3086

(b) Find P(Not Millennial | Did Not Read a Book)

P( Not Millennial | Did Not Read a Book) = P(Not Millennial and Did Not Read a Book) / P(Did Not Read a Book)

Where

∵ P(A' and B') = 1 - P(A or B)

P(Not Millennial and Did Not Read a Book) = 1 - P(Millennial or Read a Book)

∵ P(A or B) = P(A) + P(B) - P(A and B)

P(Millennial or Read a Book) = P(Read a Book) + P(Millennial) - P(Millennial and Read a Book)

P(Millennial or Read a Book) = 0.81 + 0.28 - 0.25

P(Millennial or Read a Book) = 0.84

So,

P(Not Millennial and Did Not Read a Book) = 1 - 0.84

P(Not Millennial and Did Not Read a Book) = 0.16

Also,

∵ P(A') = 1 - P(A)

P(Did Not Read a Book) = 1 - P(Read a Book)

P(Did Not Read a Book) = 1 - 0.81

P(Did Not Read a Book) = 0.19

Finally,

P( Not Millennial | Did Not Read a Book) = P(Not Millennial and Did Not Read a Book) / P(Did Not Read a Book)

P( Not Millennial | Did Not Read a Book) = 0.16/0.19

P( Not Millennial | Did Not Read a Book) = 0.8421

(c) Are being considered a millennial and having read a book in the past year independent events? Justify your answer mathematically.

Mathematically, two events are considered to be independent if the following relation holds true,

P(A and B) = P(A) × P(B)

For the given case,

P(Millennial and Read a Book) = P(Read a Book) × P(Millennial)

0.25 = 0.81 × 0.28

0.25 ≠ 0.2268

Since the relation doesn't hold true, therefore, being considered a millennial and having read a book in the past year are not independent events.

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4 years ago

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DerKrebs [107]

Answer:

Step-by-step explanation:

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3 years ago