Difference between revisions of "1981 AHSME Problems/Problem 7"

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==Solution==
 
==Solution==
The least common multiple of 2, 3, 4, and 5 is <math>2^2 \cdot 3 \cdot 5 = 60.</math> There is only one multiple of 60 between 0 and 100, so the answer is <math>\textbf{(B)}\ 1.</math>
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The least common multiple of <math>2</math>, <math>3</math>, <math>4</math>, and <math>5</math> is <math>2^2 \cdot 3 \cdot 5 = 60</math>. There is only one multiple of <math>60</math> between <math>1</math> and <math>100</math>, so the answer is <math>\textbf{(B)}\ 1.</math>
  
 
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-edited by coolmath34
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==See also==
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{{AHSME box|year=1981|num-b=6|num-a=8}}
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{{MAA Notice}}

Latest revision as of 13:38, 28 June 2025

Problem 7

How many of the first one hundred positive integers are divisible by all of the numbers $2$, $3$, $4$, and $5$?

$\textbf{(A)}\ 0\qquad\textbf{(B)}\ 1\qquad\textbf{(C)}\ 2\qquad\textbf{(D)}\ 3\qquad\textbf{(E)}\ 4$

Solution

The least common multiple of $2$, $3$, $4$, and $5$ is $2^2 \cdot 3 \cdot 5 = 60$. There is only one multiple of $60$ between $1$ and $100$, so the answer is $\textbf{(B)}\ 1.$

-edited by coolmath34

See also

1981 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 6
Followed by
Problem 8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
All AHSME Problems and Solutions

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