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AMC 8
1987 AMC 8
9
9
Part of
1987 AMC 8
Problems
(1)
1987 AJHSME Problem 9
Source:
6/25/2011
When finding the sum
1
2
+
1
3
+
1
4
+
1
5
+
1
6
+
1
7
\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}
2
1
+
3
1
+
4
1
+
5
1
+
6
1
+
7
1
, the least common denominator used is
(A)
120
(B)
210
(C)
420
(D)
840
(E)
5040
\text{(A)}\ 120 \qquad \text{(B)}\ 210 \qquad \text{(C)}\ 420 \qquad \text{(D)}\ 840 \qquad \text{(E)}\ 5040
(A)
120
(B)
210
(C)
420
(D)
840
(E)
5040
number theory
least common multiple
relatively prime
prime numbers