Question 11 is C and also question 2 is A
Answer: 
Step-by-step explanation:
Given
Complex number is 
Its conjugate is obtained by changing the sign of the original number i.e. 
The product of the two numbers is
![\Rightarrow (2-i5)(2+i5)=2^2-(5i)^2\quad \quad [(x+y)(x-y)=x^2-y^2]\\\\\Rightarrow (2-i5)(2+i5)=4-25i^2\\\\\Rightarrow (2-i5)(2+i5)=4+25=29](https://tex.z-dn.net/?f=%5CRightarrow%20%282-i5%29%282%2Bi5%29%3D2%5E2-%285i%29%5E2%5Cquad%20%5Cquad%20%5B%28x%2By%29%28x-y%29%3Dx%5E2-y%5E2%5D%5C%5C%5C%5C%5CRightarrow%20%282-i5%29%282%2Bi5%29%3D4-25i%5E2%5C%5C%5C%5C%5CRightarrow%20%282-i5%29%282%2Bi5%29%3D4%2B25%3D29)
The intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
Decibel level, dB = 10log₁₀(I/I₀) where dB = decibel level = 156, I = intensity at 156 dB and I₀ = 10⁻¹² W/m².
Since we require I, making I subject of the formula, we have
dB/10 = log₁₀(I/I₀)
Substituting the values of the variables into the equation, we have
I = 3981.072W/m²
I = 3.981 × 10³ W/m²
So, the intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
Learn more about intensity of sound here:
brainly.com/question/4431819
Answer:
29.5+/-1.11
= ( 28.39, 30.61)
Therefore, the 90% confidence interval (a,b) =( 28.39, 30.61)
Step-by-step explanation:
Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.
The confidence interval of a statistical data can be written as.
x+/-zr/√n
Given that;
Mean x = 29.5
Standard deviation r = 5.2
Number of samples n = 59
Confidence interval = 90%
z-value (at 90% confidence) = 1.645
Substituting the values we have;
29.5+/-1.645(5.2/√59)
29.5+/-1.645(0.676982337100)
29.5+/-1.113635944529
29.5+/-1.11
= ( 28.39, 30.61)
Therefore, the 90% confidence interval (a,b) =( 28.39, 30.61)
Hey there! :) The answer to your question is $12 per pound. To find a unit rate you divide $60/5= $12. To double-check, 1 pound is $12, 2 pounds is $24, 3 pounds is $36, 4 pounds is $48, and lastly 5 pounds is $60. I hope you have a great day, and keep smiling! :D Also hoped I helped! ;)
