📐 Ratios & Proportional Relationships
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Multi-Step Percent Problems

Tax, tip, discount, markup, and simple interest — percentages at work in real life.

Percent means "per hundred." Real-world problems — sales tax, restaurant tips, store discounts, price markups, and bank interest — all require converting a percent to a decimal and applying it to a base amount.

Percent Amount=Base×rate100\text{Percent Amount} = \text{Base} \times \frac{\text{rate}}{100}
🏷️Sales tax and discount together
A jacket costs $80. It is 25% off, then 8% sales tax is applied.

Step 1 — Discount: $80 × 0.25 = $20 off → $80 − $20 = $60
Step 2 — Tax: $60 × 0.08 = $4.80
Final price: $60 + $4.80 = $64.80
I=P⋅r⋅t(Simple Interest: Principal×rate×time)I = P \cdot r \cdot t \quad (\text{Simple Interest: Principal} \times \text{rate} \times \text{time})
🏦Simple interest
You deposit $500 at 4% annual interest for 3 years.

I = 500 × 0.04 × 3 = $60
Total = $500 + $60 = $560

General approach to percent problems:

1Identify the base amount and the percent rate
2Convert the percent to a decimal (divide by 100)
3Multiply: base × decimal rate = percent amount
4Add (tax, tip, markup) or subtract (discount) from the base
5If multi-step, use the result as the new base for the next step
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Remember This!

A quick mental math trick: 10% of any number is just moving the decimal one place left. Then scale up or down (e.g., 15% = 10% + 5%, and 5% = half of 10%).

✏️ Try It!

A restaurant bill is $45. You want to leave an 18% tip. How much is the tip?

Practice with CalcVerse
🔄Fraction ↔ Decimal ↔ %📈Compound Interest Predictor%Percent Calculator🍽️Tip & Bill Splitter
Take Quiz 📝 — 25 Questions