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Probability models

You might need: Calculator

Problem

Dalia owns a gravel pit. She took a random sample of rocks and counted 58 sedimentary rocks, 213 metamorphic rocks, and 522 igneous rocks.
Use the observed frequencies to create a probability model for Dalia randomly selecting one rock from her gravel pit.
Input your answers as fractions or as decimals rounded to the nearest hundredth.
Type of rockEstimated probability
Sedimentary
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
Metamorphic
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
Igneous
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
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