Question bank / Probability and conditional probability

Math · Problem-Solving and Data AnalysisEasy
Saturday Sunday Total
Adult 62 48 110
Child 52 38 90
Total 114 86 200

The table shows the number of adult and child visitors to a science museum on one Saturday and one Sunday. If one of these 200200 visitors is selected at random, what is the probability that the visitor is a child who visited on Sunday?

A

19100\frac{19}{100}

B

1945\frac{19}{45}

C

43100\frac{43}{100}

D

1943\frac{19}{43}

Show answer and explanation

Answer: A

The table shows that 3838 visitors were children who visited on Sunday. Any of the 200200 visitors could be selected, so the probability is 38200=19100\frac{38}{200} = \frac{19}{100}.

Choice B divides by the 9090 children, which gives the probability that a child visitor came on Sunday, a different question.

Why the other choices are wrong

  • B. This divides 38 by the 90 children, which gives the probability that a child visited on Sunday.
  • C. 43/100 is 86 out of 200, the probability of visiting on Sunday, whether adult or child.
  • D. This divides 38 by the 86 Sunday visitors, which gives the probability that a Sunday visitor is a child.
Ask Owl about this questionNext question

Got it wrong? On SAT Owl, Owl looks at the answer you chose and explains the exact mistake, then gives you similar questions until it sticks. Get your predicted SAT score free, or take a free full-length practice test.