SAT Percentage and Compound Changes Practice Quiz

After the first year, the investment is \( 1000 \times (1 + \frac{10}{100}) = 1000 \times 1.1 = 1100 \). After the second year, it is \( 1100 \times 1.1 = 1210 \). After the third year, it is \( 1210 \times 1.1 = 1331 \). To express this as a percentage of the initial investment: \( \frac{1331}{1000} \times 100 = 133.1% \).

After the first quarter, the revenue is \( 500000 \times (1 + \frac{20}{100}) = 500000 \times 1.2 = 600000 \). After the second quarter, it is \( 600000 \times (1 - \frac{10}{100}) = 600000 \times 0.9 = 540000 \).

After the first year, the car's value is \( 20000 \times (1 - \frac{15}{100}) = 20000 \times 0.85 = 17000 \). After the second year, it is \( 17000 \times 0.85 = 14450 \).

After 1 hour, the population is \( 500 \times 2 = 1000 \). After 2 hours, it is \( 1000 \times 2 = 2000 \). After 3 hours, it is \( 2000 \times 2 = 4000 \). To express this as a percentage of the initial population: \( \frac{4000}{500} \times 100 = 800% \).

First, calculate the discount: \( 250 \times \frac{20}{100} = 50 \). The discounted price is \( 250 - 50 = 200 \). Next, apply the 10% sales tax: \( 200 \times \frac{10}{100} = 20 \). The final price is \( 200 + 20 = 220 \).

Using the formula \( a = \frac{10}{100} \times b \), and substituting \( a = 40 \), we solve for \( b = \frac{40 \times 100}{10} = 400 \).

The value can be calculated using the formula: \( \frac{25}{100} \times 480 = 120 \).

The value is calculated as \( 200 + (\frac{60}{100} \times 200) = 200 + 120 = 320 \).

The decrease is \( 120 - 96 = 24 \). The percentage decrease is calculated as \( \frac{24}{120} \times 100 = 20% \).

The value is calculated as \( 500 - (\frac{20}{100} \times 500) = 500 - 100 = 400 \).

Using the formula \( x = \frac{45}{100} \times 800 = 360 \).

The increase is \( 325 - 250 = 75 \). The percentage increase is calculated as \( \frac{75}{250} \times 100 = 30% \).

Using the formula \( y = \frac{15}{100} \times z \), and substituting \( y = 90 \), we solve for \( z = \frac{90 \times 100}{15} = 600 \).

The value can be calculated using the formula: \( \frac{30}{100} \times 600 = 180 \).

The percentage can be calculated using the formula: \( \frac{x}{400} \times 100 \). Substituting \( x = 100 \), we get \( \frac{100}{400} \times 100 = 25% \).