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Mashcka [7]
3 years ago
7

Two planes are driving toward each other with the speeds 250 mph and 420 mph respectively. If the distance between them are 1250

miles, in how many hours they will meet?
Mathematics
1 answer:
lakkis [162]3 years ago
8 0

Answer:

They will meet in 1.866 hours.

Step-by-step explanation:

This is actually quite a simple question once we think about it in a different way.

Instead of thinking of two different planes that are going at two different speeds, think of it like this: the distance between the two planes is decreasing by 670mph (250mph + 420 mph).

Note: miles per hour is equivalent to miles/hour (<em>miles divided by hours</em> or <em>miles over hours</em>)

670m/h becomes our new rate. The rate the distance between the planes is decreasing.

Now, if the distance between them is 1250 miles, how long until they meet?

If we have miles and multiply it by hours/miles, the miles cancel out and you are left with hours.

We have miles (1250) and miles/hours (670). If we multiply these we get units of miles^2 / hours which is not what we want.

we need to multiply 1250 miles by something with the units of hours/miles.

It turns out that the reciprocal of miles/hours is hours/miles

That means we need to multiply 1250 miles by the reciprocal of 670 miles/hours

Note: the reciprocal of a fraction is the fraction flipped around. 1/2 becomes 2/1, reciprocal of 3/5 is 5/3, etc...

the reciprocal of 670 miles/hours = 1/670 miles/hours

Multiplying 1250 miles by 1/670 miles/hours is the SAME as

dividing the number of miles(1250m) by the rate(670m/h)

1250m / 670m/h = 1250m x 1/670 x h/m = 1.866 h = 1.866 hours (the miles cancel out)


<h2>Note: I explained it so you know why dividing 1250miles by 670mph gives you hours. Once you understand why, all you need to do in the future is divide the distance by the rate and you get time. </h2><h2>Distance / rate = time</h2><h2 />
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Answer:

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Step-by-step explanation:

This will help you calculate any future percentages.

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757.923 expanded form
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3 years ago
Given b(x) = |x+4], what is b(-10)?<br> -10<br> -6<br> 8<br> 14
GREYUIT [131]

Answer:

b(-10) = 6

Step-by-step explanation:

Step 1: Define

b(x) = |x + 4|

b(-10) is x = -10

Step 2: Substitute and Evaluate

b(-10) = |-10 + 4|

b(-10) = |-6|

b(-10) = 6

8 0
3 years ago
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the side of a triangle are in the extended ratio of 3:2:4 if the length of the shortest side is 6cm what is the length of the lo
Nat2105 [25]
In the ratio, the numbers are 2 for the shortest side, 3 for the middle sized side, and 4 for the longest side.

2 is to 6 cm as 4 is to x

2/6 = 4/x

2x = 4 * 6

2x = 24

x = 12

Answer: The longest side measures 12 cm.
7 0
3 years ago
PLZ HELP, AND PLZ EXPLAIN
shutvik [7]

Answer:

C

Step-by-step explanation:

To make it easy let's start by organizing our information :

  • AC=12 AND BD=8
  • ABCD is a rhombus
  • K and L are the midpoints of sides AD and CD
  • we notice that the rhombus ABCD is divided into four right triangles

What do you think of when you hear a right triangle ?

  • The pythagorian theorem !

AC and BD  are khown so let's focus on them .

If we concentrated we can notice that AB and BD are cossing each other in the midpoints . why ?

Simply because they are the diagonals of a rhombus .

ow let's apply the pythagorian theorem :

  • (AC/2)² + (BD/2)² = BC²
  • 6²+4²=52
  • BC²= 52⇒\sqrt{52}=BC

Now we khow that : AB=BC=CD=AD=\sqrt{52}

This isn't enough . Let's try to figure out a way to calculate the length of KL  wich is the base of the triangle

  • KL is parallel to AC
  • k is the midpoint of AD and L of DC

I smell something . yes! Thales theorem

  • KL/AC=DL/DC=DK/AD WE4LL TAKE OLY ONE
  • KL/12=\sqrt{52}/2*\sqrt{52}  
  • KL/12=1/2⇒ KL=6

Now we have the length of the base kl

Now the big boss the height :

  • notice that you khow the length of KL
  • BD crosses kl from its midpoint and DL = \sqrt{52} /2

What I want to do is to apply the pythgorian thaorem to khow the lenght of that small part that is not a part of the height of the triangle . I will call it D

  • DL²=(KL/2)²+D²
  • 52/4= 9+ D²
  • D² = 52/4-9 +4 SO D=2

now the height of the trigle is H= BD-D= 8-2=6

NOw the area of the triangle is :

  • A=(KL*H)/2 ⇒ A= (6*6)/2=18

THE ANSWER IS 18 SQ.UN

5 0
3 years ago
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