Proportional Reasoning- Percent

Proportional reasoning is the ability to compare ratios and understand the relationship between quantities. It involves recognizing that two ratios are equivalent.

A percent is a ratio expressed as a fraction of 100. It represents a part of a whole.

To calculate the total cost including sales tax, multiply the original price by the sales tax rate (as a decimal) and add it to the original price.

Total cost = $50 + ($50 * 0.10) = $55.

A discount is a reduction in the original price of an item, often expressed as a percentage.

To find the original price, divide the sale price by (1 - discount rate).

Original price = $47.03 / (1 - 0.05) = $49.50.

Simple interest is calculated on the principal amount only, not on the interest accrued over time.

Simple Interest = Principal x Rate x Time.

Interest rate = (Interest / (Principal x Time)) x 100 = (150 / (2000 x 3)) x 100 = 2.5%.