2020 AMC 10 A

Complete problem set with solutions and individual problem pages

Problem 2 Easy

The numbers 3,5,7, a, and b have an average (arithmetic mean) of 15 . What is the average of a and b ?

  • A.

    0

  • B.

    15

  • C.

    30

  • D.

    45

  • E.

    60

Answer:C

The arithmetic mean of the numbers 3,5,7, a, and b is equal to \frac{3+5+7+a+b}{5}=\frac{15+a+b}{5}=15. Solving for a+b, we get a+b=60. Dividing by 2 to find the average of the two numbers a and b gives \frac{60}{2}=(\mathbf{C}) 30.

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Problem 1 2020 AMC 10 A
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