Math worksheet for solving percentage increase and decrease problems with real-world scenarios.

Let's solve each problem step by step.

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Problem 1:

The normal price of a pair of sneakers is $200. This week the sneakers were on sale for only $150. By what percentage did the price decrease?

Solution:
1. Calculate the decrease in price:
\[
\text{Decrease} = \text{Original Price} - \text{Sale Price} = 200 - 150 = 50
\]
2. Calculate the percentage decrease:
\[
\text{Percentage Decrease} = \left( \frac{\text{Decrease}}{\text{Original Price}} \right) \times 100 = \left( \frac{50}{200} \right) \times 100 = 25\%
\]

Answer:
\[
\boxed{25\%}
\]

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Problem 2:

Yesterday the price of a kilogram of bananas was $2.50. Today the price was raised to $3. By what percentage did the price increase?

Solution:
1. Calculate the increase in price:
\[
\text{Increase} = \text{New Price} - \text{Old Price} = 3 - 2.50 = 0.50
\]
2. Calculate the percentage increase:
\[
\text{Percentage Increase} = \left( \frac{\text{Increase}}{\text{Old Price}} \right) \times 100 = \left( \frac{0.50}{2.50} \right) \times 100 = 20\%
\]

Answer:
\[
\boxed{20\%}
\]

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Problem 3:

The price of a liter of gasoline increased 20% compared with last year. If the new price is $1.44 per liter, what was last year’s price?

Solution:
1. Let the last year's price be \( x \).
2. The new price is 20% more than last year's price, so:
\[
\text{New Price} = x + 0.20x = 1.20x
\]
3. We know the new price is $1.44, so:
\[
1.20x = 1.44
\]
4. Solve for \( x \):
\[
x = \frac{1.44}{1.20} = 1.20
\]

Answer:
\[
\boxed{1.20}
\]

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Problem 4:

Peter earns $12.50 per hour. After complaining about his low pay, his boss decided to give him $2.50 more per hour. What percentage did his pay go up?

Solution:
1. Calculate the increase in pay:
\[
\text{Increase} = 2.50
\]
2. Calculate the percentage increase:
\[
\text{Percentage Increase} = \left( \frac{\text{Increase}}{\text{Original Pay}} \right) \times 100 = \left( \frac{2.50}{12.50} \right) \times 100 = 20\%
\]

Answer:
\[
\boxed{20\%}
\]

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Problem 5:

John kept $4,000 dollars in his bank account. After 6 years he had $5,200 in his account. By what percentage did his bank balance grow?

Solution:
1. Calculate the increase in the bank balance:
\[
\text{Increase} = \text{Final Balance} - \text{Initial Balance} = 5200 - 4000 = 1200
\]
2. Calculate the percentage increase:
\[
\text{Percentage Increase} = \left( \frac{\text{Increase}}{\text{Initial Balance}} \right) \times 100 = \left( \frac{1200}{4000} \right) \times 100 = 30\%
\]

Answer:
\[
\boxed{30\%}
\]

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Problem 6:

The rent on my house is $2,000 a month. My greedy landlord decided to increase the rent by a whopping 20%. What is the new monthly rent I have to pay?

Solution:
1. Calculate the increase in rent:
\[
\text{Increase} = 20\% \text{ of } 2000 = 0.20 \times 2000 = 400
\]
2. Calculate the new rent:
\[
\text{New Rent} = \text{Original Rent} + \text{Increase} = 2000 + 400 = 2400
\]

Answer:
\[
\boxed{2400}
\]

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Final Answers:

1. \(\boxed{25\%}\)
2. \(\boxed{20\%}\)
3. \(\boxed{1.20}\)
4. \(\boxed{20\%}\)
5. \(\boxed{30\%}\)
6. \(\boxed{2400}\)