Question

In a certain region, the number of children who have been vaccinated against rubella is twice the number who have been vaccinated against mumps. The number who have been vaccinated against both is twice the number who have been vaccinated only against mumps. If 5,000 have been vaccinated against both, how many have been vaccinated against rubella only?
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Answer Choices

  • A.
    2,500
  • B.
    7,500
  • C.
    10,000
  • D.
    15,000
  • E.
    17,500

Steps

ExplanationCalculationsHelp
We define variables for each group to avoid ambiguity.
M =
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TRANS1-A
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We define variables for each group to avoid ambiguity.
R =
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TRANS1-A
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We define variables for each group to avoid ambiguity.
B =
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TRANS1-A
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We translate into an equation.
R + B = 2(M + B)
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TRANS1-B
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TRANS1-E
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We translate into an equation.
B = 2M
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TRANS1-B
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TRANS1-E
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We substitute into the second equation and solve for .
We substitute and into the first equation and solve for .
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Final Answer

10000 (Option C): 10,000 children have been vaccinated against rubella only.