Answer:
1.

E(3) = 0.29
2. See Below
Step-by-step explanation:
1.
According to the formula we would need the derivative, so lets first calculate the derivative of f(p) given.
The rules to use would be 
Also, remember to use chain rule if there is a function inside a function. So we differentiate the "inside" function again.
Now, lets differentiate:

Now, the E(p):

We find E(3) by substituting 3 into "p":

2.
When E(p) = 1, it means the price elasticity of demand is "1". It is the called Unitary Elastic Demand. It means that for every unit change in price, there is the same unit change in demand. The changes of demand and price are proportional to each other.
Need to find the common denominator for the fractions which is 120.
Multiply by 60 for 1/6 . Multiply by 24 for 1/5. Multiply by 20 for 2/6. Multiply by 15 for 1/8.
(1)(60)/(2)(60)+(1)(24)/)5)(24)+(2)(20)/(6)(20)+(1)(15)+(8)(15)
= 60/120+18/120+40/120+15/120
= 78/120+55/120
= 139/120 or in mixed number : 1 19/120
Answer: 139/120 , 1 19/120
The total ratio is 5
The number of comedy movies watched is 12
The number of other movies watched is 18
<h3>What is a ratio?</h3>
Ratio is a comparison of two or more numbers that indicates their sizes in relation to each other. Therefore,
He has watched 2 comedy movies for every 3 other movies. The total movies he has watched is 30. Therefore,
Ratio of comedy to total movies is as follows:
number of comedy movies watched = 2 / 5 × 30 = 60 / 5 = 12
number of other movies watched = 3 / 5 × 30 = 90 / 5 = 18
Therefore,
total ratio = 5
number of comedy movies watched = 12
number of other movies watched = 18
learn more on ratios here: brainly.com/question/10080852