Ratios, Proportions, and Percent Quiz

Grade 9 · Math · Quiz

Test your skills with ratios, proportions, cross-multiplication, and percent calculations.

Questions

1. Solve: 3/8 = x/24

   1. x = 6
   2. x = 8
   3. x = 9
   4. x = 12
   Show answer

   Answer: x = 9

   Cross-multiply: 8x = 72 → x = 9.

2. 50% of 60 equals 30.

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   Answer: True

   0.50 × 60 = 30.

3. A shirt costs $30 and is 15% off. What is the sale price?

   1. $25.00
   2. $25.50
   3. $24.50
   4. $26.00
   Show answer

   Answer: $25.50

   Discount = 15% of $30 = $4.50; sale price = $30 − $4.50 = $25.50.

4. A proportion can be solved using ___-multiplication.

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   Answer: cross

   Cross-multiplication: a/b = c/d → ad = bc.

5. A population decreased from 500 to 400. What is the percent decrease?

   1. 10%
   2. 15%
   3. 20%
   4. 25%
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   Answer: 20%

   Percent decrease = (500 − 400)/500 × 100% = 100/500 × 100% = 20%.

6. The ratio 4:6 is equivalent to 2:3.

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   Answer: True

   4:6 simplifies by dividing both by 2 to get 2:3.

7. What is 15% of 80?

   1. 8
   2. 10
   3. 12
   4. 14
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   Answer: 12

   0.15 × 80 = 12.

8. If 5 apples cost $2.50, the unit rate is $___ per apple.

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   Answer: 0.50

   $2.50 ÷ 5 = $0.50 per apple.

9. Solve: 7/x = 14/10

   1. x = 3
   2. x = 4
   3. x = 5
   4. x = 6
   Show answer

   Answer: x = 5

   Cross-multiply: 14x = 70 → x = 5.

10. A store marks up a $40 item by 25%. The new price is:

    1. $45
    2. $48
    3. $50
    4. $60
    Show answer

    Answer: $50

    Markup = 25% of $40 = $10; new price = $40 + $10 = $50.

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