Can you please help me with this?

Assoli18 [71]

Answer:

Step-by-step explanation:

The diameter of each curved path is 200 feet. Since the two curved semi circular paths are equal, they would form a circle. It means that the distance around the two semi circular paths would be the circumference of the circle. Formula for determining the circumference of the circle is π × diameter. It becomes

200 × 3.14 = 628 feet

Total distance around the track would be

300 + 300 + 628 = 1228 feet

5280 feet = 1 mile

1228 feet = 1228/5280 = 0.23 mile

If he runs around the track exactly 15 times, it means that the number of miles covered is

0.23 × 15 = 3.45 miles

Since he will collect $4.50 for every mile he runs, the amount of money that he collected is

4.5 × 3.45 = $15.5

5 0

3 years ago

Can anyone help with these maths questions about transformations please?

salantis [7]

A. Reflection over y = 2

B. Reflection over y axis, reflection over y = 1

C. I'm guessing you just have to draw this one, just put the center on (2,0) and enlarge it by the scale factor

8 0

3 years ago

I the cafeteria there are 7 teachers 48 girls and 45 boys. What is the probability that a person chosen at random from the cafet

mr Goodwill [35]

Total people in the cafeteria = 7 + 48 + 45 = 100

There are 45 boys.

The probability would be the number of boys over the total number of people:

45/100, which simplifies to 9/20

7 0

2 years ago

Read 2 more answers

In the theory of learning, the rate at which a subject is memorized is assumed to be proportional to the amount that is left to

fiasKO [112]

Step-by-step explanation:

From the statement:

M: is total to be memorized

A(t): the amount memorized.

The key issue is translate this statement as equation "rate at which a subject is memorized is assumed to be proportional to the amount that is left to be memorized"

memorizing rate is $\frac{dA(t)}{dt}$ .

the amount that is left to be memorized can be expressed as the total minus the amount memorized, that is $M-A(t)$ .

So we can write

$\frac{dA(t)}{dt}=k(M-A(t))$

And that would be the differential equation for A(t).

4 0

3 years ago

In a process that manufactures bearings, 90% of the bearings meet a thickness specification. A shipment contains 500 bearings. A

vredina [299]

Answer:

c) P(270≤x≤280)=0.572

d) P(x=280)=0.091

Step-by-step explanation:

The population of bearings have a proportion p=0.90 of satisfactory thickness.

The shipments will be treated as random samples, of size n=500, taken out of the population of bearings.

As the sample size is big, we will model the amount of satisfactory bearings per shipment as a normally distributed variable (if the sample was small, a binomial distirbution would be more precise and appropiate).

The mean of this distribution will be:

$\mu_s=np=500*0.90=450$

The standard deviation will be:

$\sigma_s=\sqrt{np(1-p)}=\sqrt{500*0.90*0.10}=\sqrt{45}=6.7$

We can calculate the probability that a shipment is acceptable (at least 440 bearings meet the specification) calculating the z-score for X=440 and then the probability of this z-score:

$z=(x-\mu_s)/\sigma_s=(440-450)/6.7=-10/6.7=-1.49\\\\P(z>-1.49)=0.932$

Now, we have to create a new sampling distribution for the shipments. The size is n=300 and p=0.932.

The mean of this sampling distribution is:

$\mu=np=300*0.932=279.6$

The standard deviation will be:

$\sigma=\sqrt{np(1-p)}=\sqrt{300*0.932*0.068}=\sqrt{19}=4.36$

c) The probability that between 270 and 280 out of 300 shipments are acceptable can be calculated with the z-score and using the continuity factor, as this is modeled as a continuos variable:

$P(270\leq x\leq280)=P(269.5$

d) The probability that 280 out of 300 shipments are acceptable can be calculated using again the continuity factor correction:

$P(X=280)=P(279.5$

8 0

3 years ago