Percentage of a quantity

There’s a simple trick that makes any sort of percentage question 10x easier to answer:

of means times when it comes to percentages.

For example, 20\% of 50 means 20\% \times 50.

Finding a percentage of a quantity

If we are asked to find x\% of y, we can follow these steps:

1. Convert the percentage to a decimal by dividing it by 100.
2. Multiply the decimal by the quantity.

See converting percentages to decimals for more information on step 1.

Example: find 15\% of 200

• Convert 15\% to a decimal:
  • 15 \div 100 = 0.15
• Multiply the decimal by the quantity:
  • 0.15 \times 200 = 30
• Answer: 30

Example: find 7.5\% of 80

• Convert 7.5\% to a decimal:
  • 7.5 \div 100 = 0.075
• Multiply the decimal by the quantity:
  • 0.075 \times 80 = 6
• Answer: 6

Example: find 250\% of 40

• Convert 250\% to a decimal:
  • 250 \div 100 = 2.5
• Multiply the decimal by the quantity:
  • 2.5 \times 40 = 100
• Answer: 100

Example: find 12\frac{1}{2}\% of 160

• Convert 12\frac{1}{2}\% to a decimal:
  • 12\frac{1}{2} = 12.5
  • 12.5 \div 100 = 0.125
• Multiply the decimal by the quantity:
  • 0.125 \times 160 = 20
• Answer: 20

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