All categories

2 years ago

A map of Atlanta has a scale of 1.5 inches to 0.75 miles.

Mathematics

1 answer:

Sidana [21]2 years ago

7 0

Answer:

There is a 1.5 mile gap between the two roads.

Step-by-step explanation:

Since the scale on the map is 1.5 inches for every 0.75 miles, then 3 inches on the map would equal 1.5 miles.

You might be interested in

Write 64,500 in scientific notation

lukranit [14]

6.45 x 10 to the 4th.

5 0

2 years ago

When circuit boards used in the manufacture of compact disc players are tested, the long-run percentage of defectives is 5%. Let

sergiy2304 [10]

Answer:

(a) P(X=3) = 0.093

(b) P(X≤3) = 0.966

(c) P(X≥4) = 0.034

(d) P(1≤X≤3) = 0.688

(e) The probability that none of the 25 boards is defective is 0.277.

(f) The expected value and standard deviation of X is 1.25 and 1.089 respectively.

Step-by-step explanation:

We are given that when circuit boards used in the manufacture of compact disc players are tested, the long-run percentage of defectives is 5%.

Let X = the number of defective boards in a random sample of size, n = 25

So, X ∼ Bin(25,0.05)

The probability distribution for the binomial distribution is given by;

$P(X=r)= \binom{n}{r} \times p^{r}\times (1-p)^{n-r} ; x = 0,1,2,......$

where, n = number of trials (samples) taken = 25

r = number of success

p = probability of success which in our question is percentage

of defectivs, i.e. 5%

(a) P(X = 3) = $\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $2300 \times 0.05^{3}\times 0.95^{22}$

= 0.093

(b) P(X $\leq$ 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)

= $\binom{25}{0} \times 0.05^{0}\times (1-0.05)^{25-0}+\binom{25}{1} \times 0.05^{1}\times (1-0.05)^{25-1}+\binom{25}{2} \times 0.05^{2}\times (1-0.05)^{25-2}+\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $1 \times 1 \times 0.95^{25}+25 \times 0.05^{1}\times 0.95^{24}+300 \times 0.05^{2}\times 0.95^{23}+2300 \times 0.05^{3}\times 0.95^{22}$

= 0.966

(c) P(X $\geq$ 4) = 1 - P(X < 4) = 1 - P(X $\leq$ 3)

= 1 - 0.966

= 0.034

(d) P(1 ≤ X ≤ 3) = P(X = 1) + P(X = 2) + P(X = 3)

= $\binom{25}{1} \times 0.05^{1}\times (1-0.05)^{25-1}+\binom{25}{2} \times 0.05^{2}\times (1-0.05)^{25-2}+\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $25 \times 0.05^{1}\times 0.95^{24}+300 \times 0.05^{2}\times 0.95^{23}+2300 \times 0.05^{3}\times 0.95^{22}$

= 0.688

(e) The probability that none of the 25 boards is defective is given by = P(X = 0)

P(X = 0) = $\binom{25}{0} \times 0.05^{0}\times (1-0.05)^{25-0}$

= $1 \times 1\times 0.95^{25}$

= 0.277

(f) The expected value of X is given by;

E(X) = $n \times p$

= $25 \times 0.05$ = 1.25

The standard deviation of X is given by;

S.D.(X) = $\sqrt{n \times p \times (1-p)}$

= $\sqrt{25 \times 0.05 \times (1-0.05)}$

= 1.089

8 0

2 years ago

The circumference of the bike tire above is 83.524 inches. What is the radius of the bike tire? (Use 3.14 for .) A. 262.27 in B.

Shtirlitz [24]

Answer:

Option C. 13.3 in.

Step-by-step explanation:

Here's the required formula to find the radius of the bike tire :

$\longrightarrow{\pmb{\sf{C_{(Circle)} = 2\pi r}}}$

C = circumference
π = 3.14
r = radius

Substituting all the given values in the formula to find the radius of the bike tire :

$\begin{gathered} \qquad{\longrightarrow{\sf{C_{(Circle)} = 2\pi r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 2 \times 3.14 \times r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 6.28 \times r}}} \\ \\ \qquad{\longrightarrow{\sf{83.524 = 6.28r}}} \\ \\ \qquad{\longrightarrow{\sf{r = \frac{83.524}{6.28}}}} \\ \\ \qquad{\longrightarrow{\sf{r = 13.3 \: in}}} \\ \\ \qquad \star{\underline{\boxed{\sf{\red{r = 13.3 \: in}}}}}\end{gathered}$