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2014 CEMC Gauss (Grade 8) Problems/Problem 7

Problem

How many prime numbers are there between $10$ and $30$?

$\text{ (A) }\ 4\qquad\text{ (B) }\ 7\qquad\text{ (C) }\ 6\qquad\text{ (D) }\ 3\qquad\text{ (E) }\ 5$

Solution

Since there aren't very many prime numbers in the range from $10$ to $30$, we can list them all:

$11, 13, 17, 19, 23, 29$

Thus, the number of prime numbers between $10$ and $30$ is $\boxed {\textbf {(C) } 6}$.

~anabel.disher

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