Solve each problem. See Example 3. How many gallons of a 5% acid solution must be mixed with 5 gal of a 10% solution to obtain a 7% solution?
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
Linear Equations
Problem 76
Textbook Question
After a 20% reduction, a 42-inch HDTV sold for \$256. What was the price before the reduction?
Verified step by step guidance1
Understand that the price after a 20% reduction means the HDTV was sold for 80% of its original price, because 100% - 20% = 80%.
Let the original price be represented by . The reduced price is then .
Set up the equation based on the information given: .
To find the original price , divide both sides of the equation by 0.8: .
Simplify the division to express the original price before the reduction.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
3mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Percentage Reduction
A percentage reduction represents a decrease in the original amount by a certain percent. In this problem, a 20% reduction means the final price is 80% of the original price, since 100% - 20% = 80%. Understanding this helps relate the sale price to the original price.
Original Price Calculation
To find the original price before a percentage reduction, divide the reduced price by the remaining percentage expressed as a decimal. For example, if the price after a 20% reduction is $256, the original price is $256 ÷ 0.8. This reverses the effect of the reduction.
Recommended video:
Graph Hyperbolas NOT at the Origin
Decimal and Percentage Conversion
Percentages must be converted to decimals for calculations by dividing by 100. For instance, 20% becomes 0.20, and 80% becomes 0.80. This conversion is essential for multiplying or dividing when solving problems involving percentage changes.
Recommended video:
The Number e
Watch next
Master Introduction to Solving Linear Equtions with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice
Textbook Question
413
views
