16Hit1600
Problem-Solving and Data AnalysisEasyComplement of an event

Problem-Solving and Data Analysis practice question

The probability that a spinner lands on blue is 3/8. What is the probability that the spinner does NOT land on blue?

  1. A. 5/8Correct
  2. B. 3/8
  3. C. 1/8
  4. D. 3/5

Answer: A. 5/8

The probabilities of an event and its opposite add to 1: 1 − 3/8 = 5/8.

Why the other answers are wrong

B. 3/8
3/8 is the probability of landing ON blue.
C. 1/8
1/8 is 1 − 7/8, or 3/8 − 2/8; the complement of 3/8 is 5/8.
D. 3/5
3/5 doesn't come from 1 − 3/8. The two probabilities must sum to 1 = 8/8.

More Problem-Solving and Data Analysis questions

Not affiliated with the College Board. SAT is a trademark of the College Board.