Percentage increase

If we are asked to increase a quantity by a certain percentage, we can follow these steps:

• Find the decimal multiplier of the percentage increase.
• Multiply the original quantity by the decimal multiplier.

Finding the decimal multiplier

The decimal multiplier for a percentage increase can be found using the formula:

\text{decimal multiplier} = 1 + \left(\frac{\text{percentage increase}}{100}\right)

In other words, we convert the percentage increase to a decimal and then add 1 to it.

Finding the percentage increase

Once we’ve found the decimal multiplier, simply multiply the original quantity by the decimal multiplier to find the increased amount.

Example: Increase 120 by 15\%

• Find the decimal multiplier:
  • \text{decimal multiplier} = 1 + \left(\frac{15}{100}\right) = 1 + 0.15 = 1.15
• Multiply the original quantity by the decimal multiplier:
  • 120 \times 1.15 = 138
• Answer: 138

Example: Increase 250 by 40\%

• Find the decimal multiplier:
  • \text{decimal multiplier} = 1 + \left(\frac{40}{100}\right) = 1 + 0.4 = 1.4
• Multiply the original quantity by the decimal multiplier:
  • 250 \times 1.4 = 350
• Answer: 350

Example: Increase 80 by 12.5\%

• Find the decimal multiplier:
  • \text{decimal multiplier} = 1 + \left(\frac{12.5}{100}\right) = 1 + 0.125 = 1.125
• Multiply the original quantity by the decimal multiplier:
  • 80 \times 1.125 = 90
• Answer: 90

Example: Increase 600 by 250\%

• Find the decimal multiplier:
  • \text{decimal multiplier} = 1 + \left(\frac{250}{100}\right) = 1 + 2.5 = 3.5
• Multiply the original quantity by the decimal multiplier:
  • 600 \times 3.5 = 2100
• Answer: 2100