Answer:
a)
b)
c)
d)
Explanation:
From the question we are told that:
Population percentage 
Sample size 
Let x =customers ask for water
Let y =customers dose not ask for water with their meal
Generally the equation for y is mathematically given by

Generally the equation for pmf p(x) is mathematically given by

a)
Generally the probability that exactly 6 ask for water is mathematically given by


b)
Generally the probability that less than 9 ask for water with meal is mathematically given by




c)
Generally the probability that at least 3 ask for water with meal is mathematically given by

![p(x\geq3)=1-[p(0)+p(1)+p(2)]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5Bp%280%29%2Bp%281%29%2Bp%282%29%5D)
![p(x\geq3)=1-[0.00001+0.0015+0.0106]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.00001%2B0.0015%2B0.0106%5D)
![p(x\geq3)=1-[0.0122]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.0122%5D)

d)
Generally the mean and standard deviation of sample size is mathematically given by
Mean

Standard deviation


Input heat, Qin = 4 x 10⁵ J
Output heat, Qout = 3.5 x 10⁵ J
From the first Law of thermodynamics, obtain useful work performed as
W = Qin - Qout
= 0.5 x 10⁵ J
By definition, the efficiency is
η = W/Qin
= 100*(0.5 x 10⁵/4 x 10⁵)
= 12.5%
Answer: The efficiency is 12.5%
For a reaction to occur, energy must be absorbed to break chemical bonds
<u>Explanation:</u>
Reactions can be classified as chemical reaction, nuclear reaction, thermal reaction. So in these three reaction types, the nature of energy will only be varying.
But in order to execute a reaction, there should be breaking of existing bonds and then formation of new bonds. So for breaking of the bonds of reactants, energy should be absorbed from the surrounding.
Then the extra energy will be released after forming the products. Thus, the process of absorption of energy will lead to endothermic process and the process of releasing of energy will lead to exothermic reaction. So for a reaction to occur, energy must be absorbed to break the chemical bonds.
Answer:
Diffraction of sound wavelengths.
Explanation:
-A wave is able to bend around a corner due to the effects of diffraction. sound aves are capable of bending around corners in the same magnitude as it's wavelength making it possible to hear sounds around corners.