To find the price elasticity of demand, the formula is this:

Where dQn/dPn is the derivative of quantity demanded in respect to price

However, we were given the value of price but not quantity.

So, we simply insert the value of Each value in the demand function like this👇👇👇

From the equation, the derivative of quantity demanded in respect to price is –2. Therefore, we substitute into the equation accordingly.

You know the price elasticity of demand is treated as an absolute number. Hence, the price elasticity is 0.067. This indicates demand is relatively inelastic.

Now to the second question. To determine if a good is complementary or substitute. We simply use cross-price elasticity of demand

This is the formula for cross-price elasticity of demand

Since the derivative of quantity demanded of the notebook in respect to the price of the pen is -4.

We substitute accordingly and get -0.056. This means pen and notebook are complementary goods

To the last question, how is pen related to Joshua. This involves the income elasticity of demand

Here is the formula for income elasticity of demand

The derivative of quantity demanded in respect to Joshua's income is 0.1. Accordingly, you substitute.

Finally, the numerical value of income elasticity of demand is positive, which means, notebook is a normal good to joshua

That is all, do you understand? Leave a comment below.

And remember, if you got a question, do well to ask our telegram community: t.me/educationalquora

Source of today workings and solution: https://www.eathyreading.website/2021/03/elasticity-of-demand.html

Good morning, everyone. We would be reviewing 40 fsc 113 questions by 12:00pm Today at our telegram group. Pls, do well to participate.

Pls, we need at least 70 people to be present. Therefore, pls invite your friends and colleagues to this group: t.me/educationalquora.

Thank you for your co-operation 👌

Special announcement ‼️

For everyone writing exams tomorrow. We will review some accounting questions today at 6 pm. Pls, do well to participate actively.

And pls, also enlighten your friends by inviting them 👇👇👇

Accounting is one difficult subject that has a broad application.

Student often finds accounting difficult to understand and explain.

For this reason, we are going to be focusing especially on accounting in this group: https://chat.whatsapp.com/GhnTFswsLop1RTmEdH0sBZ

For the purpose of everyone writing exams tomorrow. Here are some quiz that you should try👇👇👇

PPC: http://t.me/QuizBot?start=RZProqXM..
DEMAND AND SUPPLY: t.me/QuizBot?start=YMPaRF3A
Equilibrium: http://t.me/QuizBot?start=qO2es4kO
Theory of cost, revenue, and profit: http://t.me/QuizBot?start=CufXqlpT
Elasticity of demand: http://t.me/QuizBot?start=miCKvYDm
elasticity of supply: http://t.me/QuizBot?start=vq8RxOSF
Theory of cost, revenue and profit: https://www.economicsonline.co.uk/Quiz/Quiz-costs-revenue-and-profits.html
PPC: https://www.economicsonline.co.uk/Quiz/Quiz-production-possibility-frontiers.html

Sociologist 😔😔😔