Drill 2 · Math · Exponentials and Radicals
SAT Math: Exponentials and Radicals (Drill 2) is a Math practice drill covering Exponentials and Radicals. It contains 5 original questions created by Brian Stewart, a Barron's test prep author with over 20 years of tutoring experience.
Exponential function questions on the SAT model growth and decay using equations of the form f(x) = ab^x. This drill covers compound interest, half-life applications, fractional exponents, and interpreting what the base and initial value represent in context.
Question 1. An investor deposits $1,000 into an account that earns 5% interest compounded annually. A = 1,000(1.05)t. What is the amount after 2 years, to the nearest dollar?
Explanation: A = 1,000(1.05)2 = 1,000(1.1025) = $1,102.50, rounds to $1,103. Choice B is simple interest.
Question 2. What is the value of 4−3/2?
Explanation: 4−3/2 = 1/43/2. 41/2 = 2, then 23 = 8. So 1/8. Negative exponents don't make the result negative.
Question 3. A radioactive substance has a half-life of 6 hours. If a sample initially contains 800 mg, how many mg remain after 18 hours?
Explanation: 18/6 = 3 half-lives. 800 → 400 → 200 → 100.
Question 4. What is the value of 272/3?
Explanation: Cube root of 27 = 3. Then 32 = 9.
Question 5. The population of a city is modeled by P(t) = 50,000(0.97)t. Which statement best describes the trend?
Explanation: 0.97 = 1 − 0.03, so the population decreases by 3% per year.