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2 years ago

The ratio of boys to girls at the dance was 3:4. There were 60 girls at the dance. How many boys were at the dance

Mathematics

1 answer:

Kamila [148]2 years ago

3 0

the answer is 20 I believe (i'm so sorry if i'm wrong.)

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What are the coordinates of point J'?<br><br>(-2,-4)<br><br>(-2,-6)

Alla [95]

(-2,-4) is the right answer because it makes sentence

4 0

3 years ago

The U.S. government has devoted considerable funding to missile defense research over the past 20 years. The latest development

Ann [662]

Answer:

Part A:

$P(X=x)=n_{C_{x}}*p^x*(1-p)^{n-x}$

x is a binomial Random Variable.

Part B:

Value of p=0.8

Value of n=20

Part C:

P(X=15)=0.17456

Part D:

P(X≥15)=0.80417

Part E:

E(x)=16

E(x) tells us that out of 20 tracks the SBIRS will detect from 16 tracks.

Step-by-step explanation:

Part A:

Binomial Distribution is used because the number of tracks and the probability to find the intruding object is constant for all tracks

It means:

$P(X=x)=n_{C_{x}}*p^x*(1-p)^{n-x}$

x is a binomial Random Variable.

Part B:

Value of p=0.8

Value of n=20

Part C:

x=15

$P(X=15)=20_{C_{15}}*0.8^{15}*(1-0.8)^{20-15}\\$

By solving above Expression:

P(X=15)=0.17456

Part D:

P(X≥15)=P(X=15)+P(X=17)+P(X=16)+P(X=18)+P(X=19)+P(X=20)

$P(X=15)=20_{C_{15}}*0.8^{15}*(1-0.8)^{20-15}\\$

P(X=15)=0.17456

$P(X=16)=20_{C_{16}}*0.8^{16}*(1-0.8)^{20-16}\\P(X=16)=0.21819$

$P(X=17)=20_{C_{17}}*0.8^{17}*(1-0.8)^{20-17}\\P(X=17)=0.20536$

$P(X=18)=20_{C_{18}}*0.8^{18}*(1-0.8)^{20-18}\\P(X=18)=0.13691\\\\P(X=19)=20_{C_{19}}*0.8^{19}*(1-0.8)^{20-19}\\P(X=19)=0.05765\\\\P(X=20)=20_{C_{20}}*0.8^{20}*(1-0.8)^{20-20}\\P(X=20)=0.01153$

Now, Adding Probabilities:

$P(X=15)+P(X=17)+P(X=16)+P(X=18)+P(X=19)+P(X=20)\\=0.17456+0.21819+0.20536+0.13691+0.05765+0.01153\\$

P(X≥15)=0.80417

Part E:

Mean Distribution:

E(x)=n*p

E(x)=20*0.8

E(x)=16

E(x) tells us that out of 20 tracks the SBIRS will detect from 16 tracks.

6 0

3 years ago

The arcade has a floor that is 120 feet by 75 feet. A scale drawing of the floor on grid paper uses a scale of 1 in: 5. Feet. Wh

ArbitrLikvidat [17]

Answer:

2 feet by 1.25 feet

Step-by-step explanation:

The arcade floor has dimensions 120 ft by 75 ft.

The scale of the drawing on grid paper is 1 in : 5 feet. This is a reduced scale. This means that the size of the arcade floor was reduced in the drawing.

Let us simply the ratio 1 in : 5 feet.

1 foot = 12 inches

=> 5 feet = 5 * 12 = 60 inches

The ratio can be rewritten as 1 in : 60 in = 1 : 60.

Hence, multiply the individual dimensions of the arcade floor by $\frac{1}{60}$ .