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Sav [38]
1 year ago
11

The length of a Train A is 480 m and it takes 2 minutes to cross a tunnel of length 1,320 m. The length of a Train B, which is s

lower than Train A, is 420 m. Both the trains start at the same time from the opposite directions. If the difference between their speeds is 18 km/h, find the time they take to cross each other. (Enter only the number)
Mathematics
1 answer:
nasty-shy [4]1 year ago
4 0

Answer: 52.94

Step-by-step explanation:

Length of train A = 480m

Tunnel length = 1320m

Time taken to cross tunnel = 2 mins = 120sec

Length of train B = 420m

Train B is slower than train A

Difference between their speed = 18km/hr

18km/hr = (18×1000)/3600 = 5m/s

Speed of train A :

Speed = distance / time

Speed = 1320 / 120 = 11m/s

Therefore, speed of train B :

(11 - 5)m/s = 6m/s

Relative speed of the two trains is therefore;

(Speed of A + speed of B)

Note : they are moving in opposite direction

( 11 + 6)m/s = 17m/s

Therefore time taken to cross each other :

(Sum of the length of both trains / relative speed of the trains)

Time taken = (480m + 420m) / (17m/s)

Time taken = 900m / 17m/s

Time taken = 52.94s

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IrinaK [193]

Answer:

it should be D....due to the fact that opposite over adjacent for the missing length



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1 year ago
What is the true solution to In 20+In 5= 2 In x?<br><br>#31<br>​
Neko [114]

Answer:

ln20+ln5=2lnx

ln(20x5)=lnx^2

ln100=1nx^2

100=x^2

square root

x=10

Hope This Helps!

5 0
2 years ago
Point I is on line segment H J ‾ HJ . Given H I = 2 x , HI=2x, H J = 4 x , HJ=4x, and I J = 4 x − 10 , IJ=4x−10, determine the n
Cloud [144]

Answer:

<h3>10</h3>

Step-by-step explanation:

If point I is on the line segment HJ, then HI+IJ = HJ

Given the parameters

H I = 2 x

H J = 4 x

IJ=4x−10

Substituting the given parameters into the formula;

2x+4x-10 = 4x

6x-10 = 4x

collect like terms

6x-4x = 10

2x = 10

divide both sides b 2;

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x = 5

Since IJ = 4x-10

Substitute x = 5 into IJ

IJ = 4(5)-10

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5 0
2 years ago
Read 2 more answers
A recent study found that 51 children who watched a commercial for Walker Crisps (potato chips) featuring a long-standing sports
hichkok12 [17]

Answer:

1

The claim is that the mean amount of Walker Crisps eaten was significantly higher for the children who watched the sports celebrity- endorsed Walker Crisps commercial

2

The kind of test to use is a t -test because a t -test is used to check if there is a difference between means of a population

3

t  =  3.054

4

The p-value  is   p-value  =  P(Z >  3.054) = 0.0011291

5

The conclusion is  

There is sufficient evidence to conclude that the mean amount of Walker Crisps eaten was significantly higher for the children who watched the sports celebrity- endorsed Walker Crisps commercial

The test statistics is  

Step-by-step explanation:

From the question we are told that

   The first sample size is  n_1  =  51

    The first sample  mean is \mu_1  =  36

    The second sample size is  n_2  =  41

    The second sample  size is  \mu_2  =  25

     The first standard deviation is  \sigma _1  =  21.4 \  g

    The second standard deviation is  \sigma _2  =  12.8 \  g

  The  level of significance is  \alpha =  0.05

The  null hypothesis is  H_o  :  \mu_1 = \mu_ 2

The  alternative hypothesis is  H_a :  \mu_1 > \mu_2

Generally the test statistics is mathematically represented as

    t  =  \frac{\= x_1 - \= x_2}{ \sqrt{ \frac{s_1^2}{n_1}  + \frac{s_2^2}{n_2}  } }

=>   t  =  \frac{ 36 - 25}{ \sqrt{ \frac{ 21.4^2}{51}  + \frac{ 12.8^2}{41}  } }

=> t  =  3.054

The  p-value is mathematically represented as

     p-value  =  P(Z >  3.054)

Generally from the z table  

             P(Z >  3.054) =  0.0011291

=>   p-value  =  P(Z >  3.054) = 0.0011291

From the values obtained  we see that p-value  < \alpha so  the null hypothesis is rejected

Thus the conclusion is  

  There is sufficient evidence to conclude that the mean amount of Walker Crisps eaten was significantly higher for the children who watched the sports celebrity- endorsed Walker Crisps commercial

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