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 $\frac{100}{400} \times 100 = 25%$.