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3 years ago

A train is 1000 metres long. It is travelling at a constant speed, and approaches a

Mathematics

1 answer:

jolli1 [7]3 years ago

4 0

Answer:

240kmh

Step-by-step explanation:

The distance that the train traveled in 30s is the difference of the total length of the tunnel and the train (2000m). This means it travels 2000m/30s. This ratio is the same as 240000/3600s or 240km/1hr.

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the formula to find the period of orbit a satellite around a planet is T^2=(4pi^2/GM)r^3 where r is the orbits mean radius. If y

Oxana [17]

Answer:

The correct answer is r = ∛GM*T²/4π²

Step-by-step explanation:

Let's rewrite the formula to find the period of orbit of a satellite around a planet, to solve for r, this way:

T^2=(4pi^2/GM)r^3

T² = (4π²/GM) * r³

r³ = T²/ (4π²/GM)

r³ = T² * GM/4π²

r³ = GMT²/4π²

∛r³ = ∛GM*T²/4π²

r = ∛GM*T²/4π²

The correct answer is r = ∛GM*T²/4π²

7 0

3 years ago

The state medical school has discovered a new test for tuberculosis. (If the test indicates a person has tuberculosis, the

Inessa [10]

The probability according to the given scenario is:

(a) 0.0395

(b) 0.95

(c) 0.076

The given values are:

$P(B/A) = 0.79$
$P(A) = 0.05$

(a)

The probability that the b/w has tuberculosis as well as having (+) test will be:

→ $P(A \cap B) = P(B/A).P(A)$

By substituting the values, we get

→ $= 0.79\times 0.05$

→ $= 0.0395$

(b)

The probability that a person does not have tuberculosis will be:

→ $P(A') = 1-P(A)$

→ $=1-0.05$

→ $= 0.95$

(c)

The person does not have tuberculosis as well as have a (+) test, the probability will be:

→ $P(A' \cap B) = P(A').P(B/A')$

→ $= 0.95\times 0.08$

→ $= 0.076$

Learn more:

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8 0

2 years ago

he price of a pair of shoes increases from $68 to $77. What is the percent increase to the nearest percent?

tekilochka [14]

Answer:

an increase of 12%

Step-by-step explanation:

68 divided by 77 is 0.88 approximately

100-88 is 12

Tip:

do this for increase and decrease in percentage question

divide small number by big number, and subtract the quotient from 100

8 0

3 years ago

Read 2 more answers

Tripp and Rico are two dogs. Tripp weighs exactly 35 pounds more than Rico. Together, they weigh exactly 49 pounds. How much doe

babymother [125]

Call the weights of the two dogs $t$ and $r$ .

We know that Tripp weights 35lbs more than Rico, or:
$t=r+35$

We also know that the total weight of both dogs is 49lbs.:
$t+r=49$

Now, by substitution:
$(r+35)+r=49$
$2r+35=49$
$2r+35-35=49-35$
$2r=14$
$r=\frac{14}{2}$
$r=7$
Rico weighs 7lbs.

Then:
$t=r+35$
$t=7+35$
$t=42$
Tripp weighs 42lbs.

To check our work:
$t+r=49$
$42+7=49$
$49=49$ CHECK!

5 0

3 years ago

ZA and B are supplementary angles. If mA (x - 9)° and

Verizon [17]

The measurement of ∠B is 168°

Given,

In the question:

Angle A and Angle B are supplementary angles.

If mA (x - 9)° and m/B= (7x + 21)°

To find the measure of ∠B

Now, According to the question;

What are supplementary angles?

Two angles are Supplementary when they add up to 180 degrees.

Now, ∠A+∠B = 180°

So,

⇒(x - 9)˚+(7x + 21)°=180°

=> 8x +12 = 180°

=> 8x = 180° - 12

=> 8x = 168

=> x = 168/8

=> x = 21

For the measure of ∠B :

∠B = (7x + 21)

∠B = 7 x 21 + 21

∠B = 168°

Hence, The measurement of ∠B is 168°

Learn more about Supplementary angles at:

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5 0

1 year ago