2021 Simple Interest and Percent Change

Front

What is simple interest?

Back

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

Front

How do you calculate simple interest?

Back

Simple Interest (SI) = Principal (P) × Rate (R) × Time (T) / 100

Front

If Emilio borrows $1200 at 8% simple interest for 2 years, how much interest will he pay?

Back

Interest = $1200 × 8 × 2 / 100 = $192

Front

What is the total amount Emilio has to pay back after 2 years?

Back

Total Amount = Principal + Interest = $1200 + $192 = $1392

Front

What does percent change represent?

Back

Percent change represents the degree of change over time, expressed as a percentage of the original value.

Front

How do you calculate percent change?

Back

Percent Change = (New Value - Old Value) / Old Value × 100

Front

If 200 children attended a play and 40% were boys, how many boys attended?

Back

Number of boys = 40% of 200 = 0.4 × 200 = 80 boys.

Front

If 200 children attended a play and 40% were boys, how many girls attended?

Back

Number of girls = Total - Number of boys = 200 - 80 = 120 girls.

Front

What is 75% of a number?

Back

75% of a number can be calculated by multiplying the number by 0.75.

Front

If 75% of what number is 27, how do you find that number?

Back

Let the number be x. Then, 0.75x = 27, so x = 27 / 0.75 = 36.