User:
• Matrices
• Algebra
• Geometry
• Graphs and functions
• Trigonometry
• Coordinate geometry
• Combinatorics
 Suma y resta Producto por escalar Producto Inversa
 Monomials Polynomials Special products Equations Quadratic equations Radical expressions Systems of equations Sequences and series Inner product Exponential equations Matrices Determinants Inverse of a matrix Logarithmic equations Systems of 3 variables equations
 2-D Shapes Areas Pythagorean Theorem Distances
 Graphs Definition of slope Positive or negative slope Determine slope of a line Equation of a line Equation of a line (from graph) Quadratic function Parallel, coincident and intersecting lines Asymptotes Limits Distances Continuity and discontinuities
 Sine Cosine Tangent Cosecant Secant Cotangent Trigonometric identities Law of cosines Law of sines
 Equations of a straight line Parallel, coincident and intersecting lines Distances Angles in space Inner product

Percent of change

# Percent of change: word problems

At a supermarket, a certain item has increased from 75 cents per pound to 81 cents per pound. What is the percent increase in the cost of the item?

$Percent\;change=\frac{New\;Value\;-\;Old\;Value}{Old\;Value}x100$

$Percent\;Change=\frac{81\;-\;75}{75}x100=\frac{6}{75}x100=0.08x100=8%$

There was an 8% increase in the cost of the item.

If the price of gas increases from $1.00 per gallon to$1.21 per gallon, what is the percent of increase?

$Percent\;change=\frac{New\;Value\;-\;Old\;Value}{Old\;Value}x100$

$Percent\;Change=\frac{1.21\;-\;1.00}{1.00}x100=\frac{0.21}{1.00}x100=0.21x100=21%$

The percent of increase is 21%.

As soon as a new car is purchased and driven away from the dealership, it begins to lose its value, or depreciate. Alonso bought a 1994 Plymouth Neon for 500. One year later, the value of the car was 438. What was the percent of decrease of the value of the car?

The percent of decrease was %