Question

Difficulty: MediumSolving Linear Equations

A business analyst uses the linear equation 25(3p10)1.2=0.4(p+5)\frac{2}{5}(3p - 10) - 1.2 = 0.4(p + 5) to estimate the equilibrium price pp, in dollars, of a new product. What is the equilibrium price, in dollars, of the product?

Answer: 9 dollars

Answer

The equilibrium price of the product is 99 dollars.
Converting the fraction to a decimal gives 0.4(3p10)1.2=0.4(p+5)0.4(3p - 10) - 1.2 = 0.4(p + 5). Dividing both sides by 0.40.4 results in 3p103=p+53p - 10 - 3 = p + 5, which simplifies to 3p13=p+53p - 13 = p + 5. Subtracting pp and adding 1313 to both sides gives 2p=182p = 18, and dividing by 22 results in 99.

Step-by-Step Solution

1
Convert the fraction to decimal form
0.4(3p10)1.2=0.4(p+5)0.4(3p - 10) - 1.2 = 0.4(p + 5)
Converting 25\frac{2}{5} to 0.40.4 makes all terms decimals, simplifying further operations.
2
Divide both sides of the equation by 0.40.4
(3p10)3=p+5(3p - 10) - 3 = p + 5
Since 0.40.4 is a common factor and 1.2/0.4=31.2 / 0.4 = 3, dividing both sides by 0.40.4 simplifies the coefficients.
3
Simplify the left side of the equation
3p13=p+53p - 13 = p + 5
Combine the constant terms 10-10 and 3-3 to simplify the expression.
4
Isolate the variable terms on one side
2p=182p = 18
Subtract pp from both sides and add 1313 to both sides.
5
Solve for pp
p=9p = 9
Divide both sides by 22 to find the final value.

Key Concept

Solving Linear Equations
Rate this question