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SAT Math skill page

SAT Exponential Functions Practice

Learn how exponential growth and decay show up in SAT tables, equations, and word problems.

12-18 min practice time3 questions on pageAdvanced Math
Practice time12-18 min
Question bank3 questions
Best forAdvanced Math

What this tests

What to know for this SAT skill

Dolphin question bank

Practice your skill

Question 1 of 3Easy
A population starts at 200 and doubles each year. Which expression gives the population after t years?
  1. 200 + 2t
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Correct answer

Solution walkthrough

  1. The starting value is 200 and doubling means multiplying by 2 each year, so the model is 200(2)^t.
Question 2 of 3Medium
If f(x) = 5(3)^x, what is f(2)?
  1. 15
  2. 30
  3. 45
  4. 125
Show answer and solution
Correct answerC. 45

Solution walkthrough

Question 3 of 3Hard
A value decreases by 20% each month from an initial value of 600. Which expression represents the value after m months?
  1. 600 - 20m
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Correct answer

Solution walkthrough

  1. A 20% decrease leaves 80% of the value each month, so the multiplier is 0.80.

Avoid these traps

Common mistakes on this skill

Treating growth as repeated addition

Exponential change uses a constant multiplier over equal intervals, not a constant amount added each time.

Confusing the initial value and growth factor

In a model such as a(b)^x, a is the value at x = 0 and b controls growth or decay.

Study plan

How to practice this skill in Dolphin

  1. Identify the initial value and the equal time interval in the problem.
  2. Convert the percent change into a multiplier such as 1.08 or 0.92.
  3. Check the model at x = 0 and after one interval before interpreting the requested value.
Practice exponential functions in Dolphin SAT

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FAQ

Questions about SAT Exponential Functions Practice

How can I recognize an exponential relationship?

Look for equal inputs producing equal ratios between outputs. A linear relationship instead produces equal differences.

How is exponential decay represented?

The multiplier is between 0 and 1. A 12 percent decrease, for example, uses a multiplier of 0.88.