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The quantity \(S\) of barley, in billions of bushels, that barley suppliers in a certain country are willing to produce in a year and offer for sale at a price \(P\), in dollars per bushel, is determined by the relation $$ P=1.9 S-0.7 $$ The quantity \(D\) of barley, in billions of bushels, that barley consumers are willing to purchase in a year at price \(P\) is determined by the relation $$ P=2.8-0.6 D . $$ The equilibrium price is the price at which the quantity supplied is the same as the quantity demanded. Find the equilibrium price for barley.

Short Answer

Expert verified
The equilibrium price for barley is $2.66 per bushel.

Step by step solution

01

Understanding the Problem

We need to find the equilibrium price where the quantity supplied, \(S\), equals the quantity demanded, \(D\). Both relations for \(P\) are given, one in terms of \(S\) and the other in terms of \(D\).
02

Setting Supply Equal to Demand

Because equilibrium occurs when the quantity supplied equals the quantity demanded, set \(S = D\). Thus, \(P = 1.9S - 0.7\) and \(P = 2.8 - 0.6D\) require \(1.9S - 0.7 = 2.8 - 0.6S\).
03

Solving the Equation for \(S\)

Add \(0.6S\) to both sides to get \(1.9S + 0.6S = 2.8 + 0.7\). Simplify to find \(2.5S = 3.5\).
04

Finding the Quantity Supplied at Equilibrium

Divide each side by \(2.5\) to solve for \(S\): \(S = \frac{3.5}{2.5} = 1.4\). Thus, at equilibrium, the quantity supplied (and demanded) is 1.4 billion bushels.
05

Calculating the Equilibrium Price

Substitute \(S = 1.4\) into the supply equation: \(P = 1.9(1.4) - 0.7\). Calculate \(P = 2.66\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Supply and Demand
Supply and demand are fundamental concepts in economics that explain how the quantity of a product available and the desire of consumers for it interact to determine the price. Supply refers to how much of a product, such as barley in this case, producers are willing to sell at a certain price. Generally, the higher the price, the more producers are willing to supply, as they can earn more profit. Demand is about consumer willingness to purchase goods. Typically, as the price of a product falls, more consumers are willing to buy, increasing demand. These two functions—supply and demand—fluctuate based on economic conditions, consumer preferences, and other factors. When supply and demand are perfectly balanced, it's known as equilibrium. At this point, products are supplied and demanded at the same rate, leading to a stable market price. Understanding this balance helps in predicting market behaviors.
Algebraic Equations
Algebraic equations are mathematical statements that show the relationship between quantities. Equations often incorporate variables, which stand in place for unknown values. In this context, producers and consumers' behavior is modeled with the equations:
  • Supply Equation: \(P = 1.9S - 0.7\), where \(P\) is the price in dollars per bushel, and \(S\) is the quantity supplied in billions of bushels.
  • Demand Equation: \(P = 2.8 - 0.6D\), where \(D\) is the quantity demanded.
By solving these equations, we determine at what price and quantity the market will be in equilibrium. Using algebraic manipulation, such as adding, subtracting, or dividing both sides of an equation, we can find the "unknowns"—in this case, price, and quantity. Algebra serves as the toolset for understanding economic relationships quantitatively.
Mathematical Modeling
Mathematical modeling is a technique used to represent real-world situations with mathematical forms. Through models, we simplify complex systems to better understand, analyze, and predict dynamics within that system. In economics, mathematical equations such as the ones in this exercise help us approximate how variables like price and quantity interact in markets.
  • Defining Variables: We use variables to represent quantities and prices. Here, \(S\) and \(D\) are used for supply and demand, respectively.
  • Constructing Equations: Simplified equations express relationships. Using constants and variables, we reflect how changes in one affect others. For instance, increasing supply tends to lower price.
  • Solving Equilibrium: By equating supply and demand functions, we solve for equilibrium, helping to predict market behaviors.
Mathematical modeling bridges theory and real-world implications, guiding businesses and policymakers alike.
Price Determination
Price determination is the process of establishing the price of a product in a market. It's a dynamic interaction influenced by the concepts of supply and demand. To determine the equilibrium price, we need to match the quantity that producers are willing to sell with the quantity that consumers are willing to buy. The equations presented in this exercise showcase how these quantities directly influence price:
  • Supply Function: \(P = 1.9S - 0.7\). This function indicates that the price producers seek changes with supply volume.
  • Demand Function: \(P = 2.8 - 0.6D\). Here, price is shown as influenced by the amount demanded by consumers.
At equilibrium—where supply equals demand—the balance results naturally in a stabilized market price, calculated here as \(P = 2.66\) dollars. This equilibrium price ensures no excess supply or unmet demand, enabling fluid transactions without waste or shortage.

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Most popular questions from this chapter

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