Skip to content

Percent Applications

Solve real-world problems involving discounts, tax, tips, and percent change

Written and reviewed by the Study Mondo Education TeamLast updated
🎯⭐ INTERACTIVE LESSON

Try the Interactive Version!

Learn step-by-step with practice exercises built right in.

Start Interactive Lesson →

Percent Applications

Finding a Percent of a Number

Part=Percent×Whole\text{Part} = \text{Percent} \times \text{Whole}

Example: Find 25% of 80 0.25×80=200.25 \times 80 = 20

Percent Change

Percent Change=New - OriginalOriginal×100%\text{Percent Change} = \frac{\text{New - Original}}{\text{Original}} \times 100\%

  • Positive = Increase
  • Negative = Decrease

Common Applications

Discount

Original price ×\times (1 - discount rate)

Example: 20% off \50 $$50 \times (1 - 0.20) = 50 \times 0.80 = \40$$

Tax

Price ×\times (1 + tax rate)

Example: \30 with 8% tax $$30 \times 1.08 = \32.40$$

Tip

Bill ×\times tip rate

Example: 15% tip on \40 $$40 \times 0.15 = \6$$

📚 Practice Problems

1Problem 1easy

❓ Question:

A shirt costs \25$. It is on sale for 30% off. What is the sale price?

💡 Show Solution

Solution:

Method 1 - Find discount: Discount=0.30×25=$7.50\text{Discount} = 0.30 \times 25 = \$7.50 Sale price=25−7.50=$17.50\text{Sale price} = 25 - 7.50 = \$17.50

Method 2 - Multiply by remaining percent: 25×(1−0.30)=25×0.70=$17.5025 \times (1 - 0.30) = 25 \times 0.70 = \$17.50

Answer: \17.50$

2Problem 2easy

❓ Question:

A shirt costs \25$. It is on sale for 30% off. What is the sale price?

💡 Show Solution

Solution:

Method 1 - Find discount: Discount=0.30×25=$7.50\text{Discount} = 0.30 \times 25 = \$7.50 Sale price=25−7.50=$17.50\text{Sale price} = 25 - 7.50 = \$17.50

Method 2 - Multiply by remaining percent: 25×(1−0.30)=25×0.70=$17.5025 \times (1 - 0.30) = 25 \times 0.70 = \$17.50

Answer: \17.50$

3Problem 3medium

❓ Question:

A population increased from 15,000 to 18,000. What is the percent increase?

💡 Show Solution

Solution:

Use percent change formula: Percent Change=18000−1500015000×100%\text{Percent Change} = \frac{18000 - 15000}{15000} \times 100\%

=300015000×100%= \frac{3000}{15000} \times 100\%

=0.2×100%=20%= 0.2 \times 100\% = 20\%

Answer: 20% increase

4Problem 4medium

❓ Question:

A population increased from 15,000 to 18,000. What is the percent increase?

💡 Show Solution

Solution:

Use percent change formula: Percent Change=18000−1500015000×100%\text{Percent Change} = \frac{18000 - 15000}{15000} \times 100\%

=300015000×100%= \frac{3000}{15000} \times 100\%

=0.2×100%=20%= 0.2 \times 100\% = 20\%

Answer: 20% increase

5Problem 5hard

❓ Question:

A meal costs \45$. You want to leave a 18% tip and there is 7% sales tax. What is the total amount you pay?

💡 Show Solution

Solution:

Step 1: Add tax to the meal 45×1.07=$48.1545 \times 1.07 = \$48.15

Step 2: Calculate tip (on original meal) 45×0.18=$8.1045 \times 0.18 = \$8.10

Step 3: Total 48.15+8.10=$56.2548.15 + 8.10 = \$56.25

Answer: \56.25$

6Problem 6hard

❓ Question:

A meal costs \45$. You want to leave a 18% tip and there is 7% sales tax. What is the total amount you pay?

💡 Show Solution

Solution:

Step 1: Add tax to the meal 45×1.07=$48.1545 \times 1.07 = \$48.15

Step 2: Calculate tip (on original meal) 45×0.18=$8.1045 \times 0.18 = \$8.10

Step 3: Total 48.15+8.10=$56.2548.15 + 8.10 = \$56.25

Answer: \56.25$

Explain using:
← Previous Topic
Solving Proportions
Next Topic →
Percent of Change
🎴

Practice with Flashcards

Rate this topic's cards with spaced repetition. Cards join your deck when you finish a topic's lesson and take its exit quiz.

📖

Browse All Topics

Explore more Grade 7 Math topics

📌 Related Topics in Proportions and Percents

Solving ProportionsPercent of ChangeSimple Interest

❓ Frequently Asked Questions

What is Percent Applications?▾
Solve real-world problems involving discounts, tax, tips, and percent change
How can I study Percent Applications effectively?▾
Start by reading the study notes and working through the examples on this page. Then use the flashcards to test your recall. Practice with the 6 problems provided, checking solutions as you go. Regular review and active practice are key to retention.
Is this Percent Applications study guide free?▾
Yes — all study notes, flashcards, and practice problems for Percent Applications on Study Mondo are free to access. No account is needed.
What course covers Percent Applications?▾
Percent Applications is part of the Grade 7 Math course on Study Mondo, specifically in the Proportions and Percents section. You can explore the full course for more related topics and practice resources.
Are there practice problems for Percent Applications?▾
Yes, this page includes 6 practice problems with detailed solutions. Each problem includes a step-by-step explanation to help you understand the approach.