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Mashutka [201]
3 years ago
13

A dome of a building is in the form of a hemisphere from inside it was whitewashed at the cost of rupees 4989.60 if the cost of

white washing is rupees 20 per meter square find the inside surface area of dome and volume of air inside the dome
Mathematics
1 answer:
Luda [366]3 years ago
6 0

Answer: 249.48\ m^2; 369.168\ m^3

Step-by-step explanation:

Given

Cost of white-washing =Rs. 4989.60

Rate =20 per meter square

So, inside area of = \dfrac{4989.60}{20}=249.48\ m^2

The surface area of dome= 4\pi\ r^2=249.48

4\times 3.142\times r^2=249.48\\r^2=\frac{249.48}{4\times 3.142}=19.85\\r=4.455\ m

The volume of air in the dome V=\frac{4}{3}\pi r^3

V=\frac{4}{3}\cdot 3.142\cdot (4.45)^3\\V=369.17\ m^3

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a

The decision rule  is  

Reject the null hypothesis

  The conclusion is  

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b

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Step-by-step explanation:

From the question we are told that

    The sample size is  n  =  36

    The first sample mean is  \= x_1   =  11.4

    The first standard deviation is  s_1 =  2.5

    The second sample mean is   \= x_2 =  9.9

     The second standard deviation is  s_2 =  3.0

      The level of significance is  \alpha  =  0.05

The null hypothesis is  H_o  :  \mu_1 - \mu_2 = 0

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      z =  \frac{ (\= x_1 - \= x_2 ) - (\mu_1 - \mu_2 ) }{ \sqrt{ \frac{s_1^2 }{n} + \frac{s_2^2 }{ n}  } }

=>    z =  \frac{ ( 11.4  - 9.9) - 0  }{ \sqrt{ \frac{2.5^2 }{36} + \frac{ 3^2 }{36 }  } }

=>     z = 2.3

From the z table  the area under the normal curve to the left corresponding to  2.3 is  

       P( Z >  2.3 ) =  0.010724

Generally the p-value is mathematically represented as

      p-value =  2 * P( Z >  2.3 )

=>    p-value  =  2 * 0.010724

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From the value obtained we see that  p-value  <  \alpha hence  

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Reject the null hypothesis

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